Checksum should be allowed to be a single dictionary at the top level scope only, even for bundles/extensions (where there are top level sources as well)

[Micket]

Instead of having it per bundle component/extensions, we should allow the checksum block to be placed outside.

We should also encourage that use pattern. It would likely simplify a lot of bundles making them significantly shorter, and probably simplify some code as well.

Example of current situation:

crates = [
    ('autocfg', '1.1.0'),
    ('bitflags', '1.3.2'),
    ('cfg-if', '1.0.0'),
    ('indoc', '1.0.9'),
    ('itoa', '1.0.9'),
    ('libc', '0.2.147'),
    ('lock_api', '0.4.10'),
    ('memmap2', '0.5.10'),
    ('memoffset', '0.8.0'),
    ('once_cell', '1.18.0'),
    ('parking_lot', '0.12.1'),
    ('parking_lot_core', '0.9.8'),
    ('proc-macro2', '1.0.66'),
    ('pyo3', '0.18.3'),
    ('pyo3-build-config', '0.18.3'),
    ('pyo3-ffi', '0.18.3'),
    ('pyo3-macros', '0.18.3'),
    ('pyo3-macros-backend', '0.18.3'),
    ('quote', '1.0.31'),
    ('redox_syscall', '0.3.5'),
    ('ryu', '1.0.15'),
    ('scopeguard', '1.2.0'),
    ('serde', '1.0.171'),
    ('serde_derive', '1.0.171'),
    ('serde_json', '1.0.103'),
    ('smallvec', '1.11.0'),
    ('syn', '1.0.109'),
    ('syn', '2.0.26'),
    ('target-lexicon', '0.12.10'),
    ('unicode-ident', '1.0.11'),
    ('unindent', '0.1.11'),
]

exts_list = [
    ('huggingface_hub', '0.13.4', {
        'checksums': ['db83d9c2f76aed8cf49893ffadd6be24e82074da2f64b1d36b8ba40eb255e115'],
    }),
    ('safetensors', '0.3.0', {
        'checksums': ['5be8b2fccdc6aec84c9d6732180575fe1ba3afc559cbe96e2301eacc45c5b9a6'],
    }),
    (name, version, {
        'checksums': ['745c54f7b7985a18e08bd66c997b018c1c3fef99bbb8c018879a6f85571782f5'],
    }),
]

checksums = [
    {'autocfg-1.1.0.tar.gz': 'd468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa'},
    {'bitflags-1.3.2.tar.gz': 'bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a'},
    {'cfg-if-1.0.0.tar.gz': 'baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd'},
    {'indoc-1.0.9.tar.gz': 'bfa799dd5ed20a7e349f3b4639aa80d74549c81716d9ec4f994c9b5815598306'},
    {'itoa-1.0.9.tar.gz': 'af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38'},
    {'libc-0.2.147.tar.gz': 'b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3'},
    {'lock_api-0.4.10.tar.gz': 'c1cc9717a20b1bb222f333e6a92fd32f7d8a18ddc5a3191a11af45dcbf4dcd16'},
    {'memmap2-0.5.10.tar.gz': '83faa42c0a078c393f6b29d5db232d8be22776a891f8f56e5284faee4a20b327'},
    {'memoffset-0.8.0.tar.gz': 'd61c719bcfbcf5d62b3a09efa6088de8c54bc0bfcd3ea7ae39fcc186108b8de1'},
    {'once_cell-1.18.0.tar.gz': 'dd8b5dd2ae5ed71462c540258bedcb51965123ad7e7ccf4b9a8cafaa4a63576d'},
    {'parking_lot-0.12.1.tar.gz': '3742b2c103b9f06bc9fff0a37ff4912935851bee6d36f3c02bcc755bcfec228f'},
    {'parking_lot_core-0.9.8.tar.gz': '93f00c865fe7cabf650081affecd3871070f26767e7b2070a3ffae14c654b447'},
    {'proc-macro2-1.0.66.tar.gz': '18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9'},
    {'pyo3-0.18.3.tar.gz': 'e3b1ac5b3731ba34fdaa9785f8d74d17448cd18f30cf19e0c7e7b1fdb5272109'},
    {'pyo3-build-config-0.18.3.tar.gz': '9cb946f5ac61bb61a5014924910d936ebd2b23b705f7a4a3c40b05c720b079a3'},
    {'pyo3-ffi-0.18.3.tar.gz': 'fd4d7c5337821916ea2a1d21d1092e8443cf34879e53a0ac653fbb98f44ff65c'},
    {'pyo3-macros-0.18.3.tar.gz': 'a9d39c55dab3fc5a4b25bbd1ac10a2da452c4aca13bb450f22818a002e29648d'},
    {'pyo3-macros-backend-0.18.3.tar.gz': '97daff08a4c48320587b5224cc98d609e3c27b6d437315bd40b605c98eeb5918'},
    {'quote-1.0.31.tar.gz': '5fe8a65d69dd0808184ebb5f836ab526bb259db23c657efa38711b1072ee47f0'},
    {'redox_syscall-0.3.5.tar.gz': '567664f262709473930a4bf9e51bf2ebf3348f2e748ccc50dea20646858f8f29'},
    {'ryu-1.0.15.tar.gz': '1ad4cc8da4ef723ed60bced201181d83791ad433213d8c24efffda1eec85d741'},
    {'scopeguard-1.2.0.tar.gz': '94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49'},
    {'serde-1.0.171.tar.gz': '30e27d1e4fd7659406c492fd6cfaf2066ba8773de45ca75e855590f856dc34a9'},
    {'serde_derive-1.0.171.tar.gz': '389894603bd18c46fa56231694f8d827779c0951a667087194cf9de94ed24682'},
    {'serde_json-1.0.103.tar.gz': 'd03b412469450d4404fe8499a268edd7f8b79fecb074b0d812ad64ca21f4031b'},
    {'smallvec-1.11.0.tar.gz': '62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9'},
    {'syn-1.0.109.tar.gz': '72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237'},
    {'syn-2.0.26.tar.gz': '45c3457aacde3c65315de5031ec191ce46604304d2446e803d71ade03308d970'},
    {'target-lexicon-0.12.10.tar.gz': '1d2faeef5759ab89935255b1a4cd98e0baf99d1085e37d36599c625dac49ae8e'},
    {'unicode-ident-1.0.11.tar.gz': '301abaae475aa91687eb82514b328ab47a211a533026cb25fc3e519b86adfc3c'},
    {'unindent-0.1.11.tar.gz': 'e1766d682d402817b5ac4490b3c3002d91dfa0d22812f341609f97b08757359c'},
]

and what we could change it into:

crates = [
    ('autocfg', '1.1.0'),
    ('bitflags', '1.3.2'),
    ('cfg-if', '1.0.0'),
    ('indoc', '1.0.9'),
    ('itoa', '1.0.9'),
    ('libc', '0.2.147'),
    ('lock_api', '0.4.10'),
    ('memmap2', '0.5.10'),
    ('memoffset', '0.8.0'),
    ('once_cell', '1.18.0'),
    ('parking_lot', '0.12.1'),
    ('parking_lot_core', '0.9.8'),
    ('proc-macro2', '1.0.66'),
    ('pyo3', '0.18.3'),
    ('pyo3-build-config', '0.18.3'),
    ('pyo3-ffi', '0.18.3'),
    ('pyo3-macros', '0.18.3'),
    ('pyo3-macros-backend', '0.18.3'),
    ('quote', '1.0.31'),
    ('redox_syscall', '0.3.5'),
    ('ryu', '1.0.15'),
    ('scopeguard', '1.2.0'),
    ('serde', '1.0.171'),
    ('serde_derive', '1.0.171'),
    ('serde_json', '1.0.103'),
    ('smallvec', '1.11.0'),
    ('syn', '1.0.109'),
    ('syn', '2.0.26'),
    ('target-lexicon', '0.12.10'),
    ('unicode-ident', '1.0.11'),
    ('unindent', '0.1.11'),
]

exts_list = [
    ('huggingface_hub', '0.13.4'),
    ('safetensors', '0.3.0'),
    (name, version),
]

checksums = {
    'hugginface_hub-0.13.4.tar.gz': 'db83d9c2f76aed8cf49893ffadd6be24e82074da2f64b1d36b8ba40eb255e115',
    'safetensors-0.3.0.tar.gz': '5be8b2fccdc6aec84c9d6732180575fe1ba3afc559cbe96e2301eacc45c5b9a6',
    'timm-0.5.6.tar.gz': '745c54f7b7985a18e08bd66c997b018c1c3fef99bbb8c018879a6f85571782f5',
    'autocfg-1.1.0.tar.gz': 'd468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa',
    'bitflags-1.3.2.tar.gz': 'bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a',
    'cfg-if-1.0.0.tar.gz': 'baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd',
    'indoc-1.0.9.tar.gz': 'bfa799dd5ed20a7e349f3b4639aa80d74549c81716d9ec4f994c9b5815598306',
    'itoa-1.0.9.tar.gz': 'af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38',
    'libc-0.2.147.tar.gz': 'b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3',
    'lock_api-0.4.10.tar.gz': 'c1cc9717a20b1bb222f333e6a92fd32f7d8a18ddc5a3191a11af45dcbf4dcd16',
    'memmap2-0.5.10.tar.gz': '83faa42c0a078c393f6b29d5db232d8be22776a891f8f56e5284faee4a20b327',
    'memoffset-0.8.0.tar.gz': 'd61c719bcfbcf5d62b3a09efa6088de8c54bc0bfcd3ea7ae39fcc186108b8de1',
    'once_cell-1.18.0.tar.gz': 'dd8b5dd2ae5ed71462c540258bedcb51965123ad7e7ccf4b9a8cafaa4a63576d',
    'parking_lot-0.12.1.tar.gz': '3742b2c103b9f06bc9fff0a37ff4912935851bee6d36f3c02bcc755bcfec228f',
    'parking_lot_core-0.9.8.tar.gz': '93f00c865fe7cabf650081affecd3871070f26767e7b2070a3ffae14c654b447',
    'proc-macro2-1.0.66.tar.gz': '18fb31db3f9bddb2ea821cde30a9f70117e3f119938b5ee630b7403aa6e2ead9',
    'pyo3-0.18.3.tar.gz': 'e3b1ac5b3731ba34fdaa9785f8d74d17448cd18f30cf19e0c7e7b1fdb5272109',
    'pyo3-build-config-0.18.3.tar.gz': '9cb946f5ac61bb61a5014924910d936ebd2b23b705f7a4a3c40b05c720b079a3',
    'pyo3-ffi-0.18.3.tar.gz': 'fd4d7c5337821916ea2a1d21d1092e8443cf34879e53a0ac653fbb98f44ff65c',
    'pyo3-macros-0.18.3.tar.gz': 'a9d39c55dab3fc5a4b25bbd1ac10a2da452c4aca13bb450f22818a002e29648d',
    'pyo3-macros-backend-0.18.3.tar.gz': '97daff08a4c48320587b5224cc98d609e3c27b6d437315bd40b605c98eeb5918',
    'quote-1.0.31.tar.gz': '5fe8a65d69dd0808184ebb5f836ab526bb259db23c657efa38711b1072ee47f0',
    'redox_syscall-0.3.5.tar.gz': '567664f262709473930a4bf9e51bf2ebf3348f2e748ccc50dea20646858f8f29',
    'ryu-1.0.15.tar.gz': '1ad4cc8da4ef723ed60bced201181d83791ad433213d8c24efffda1eec85d741',
    'scopeguard-1.2.0.tar.gz': '94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49',
    'serde-1.0.171.tar.gz': '30e27d1e4fd7659406c492fd6cfaf2066ba8773de45ca75e855590f856dc34a9',
    'serde_derive-1.0.171.tar.gz': '389894603bd18c46fa56231694f8d827779c0951a667087194cf9de94ed24682',
    'serde_json-1.0.103.tar.gz': 'd03b412469450d4404fe8499a268edd7f8b79fecb074b0d812ad64ca21f4031b',
    'smallvec-1.11.0.tar.gz': '62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9',
    'syn-1.0.109.tar.gz': '72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237',
    'syn-2.0.26.tar.gz': '45c3457aacde3c65315de5031ec191ce46604304d2446e803d71ade03308d970',
    'target-lexicon-0.12.10.tar.gz': '1d2faeef5759ab89935255b1a4cd98e0baf99d1085e37d36599c625dac49ae8e',
    'unicode-ident-1.0.11.tar.gz': '301abaae475aa91687eb82514b328ab47a211a533026cb25fc3e519b86adfc3c',
    'unindent-0.1.11.tar.gz': 'e1766d682d402817b5ac4490b3c3002d91dfa0d22812f341609f97b08757359c',
}

Also, checksums should just be a dictionary, instead of a list of dictionaries.