Accounts Cache for Verkle/Kaustinen

[agnxsh]

Rewrite of accounts cache in favour of Verkle Specs, Notable changes:

1. No storage trie, as storage is now a part of the unified Verkle Trie (EIP 6800)
2. Changing the format of Witness Data and Witness Cache
3. Changing the trie in AccountsCache to a VerkleTrie
   4. Changing the format of rootHash to a 32-byte array
4. Dealing with getter and setter functions related to contract code differently as EIP6800 introduces chunkifyCode
5. Dealing with getter and setter functions related to storage differently because of 1)
6. Added the checker function of whether the account is Empty or not
7. Added the persist code for AccountsCache
8. Added a placeholder for deleteAccountBytes, since deletion is kept like that as per spec and geth

Still a draft PR, not tested yet. Though underlying functions related to verkle-based accounts are tested. Verkle's account cache directly uses #2133

[advaita-saha]

The rootHash() return type was KeccakHash which has been kept intact to preserve the API and smoothen out future integration

[agnxsh]

@advaita-saha IsEmptyVerkleAccount should be false in the getAccount check, only then the flag is Alive

[advaita-saha]

@advaita-saha IsEmptyVerkleAccount should be false in the getAccount check, only then the flag is Alive

Ahh my bad

[advaita-saha]

Missing Items @agnxsh
Few of them needs more discussion

• originalStorageValue
• setStorage
• clearStorage
• cachedStorage (iterator)
• update
• witnessData
• collectWitnessData

Lasty figure out the getContractCode()

[advaita-saha]

Note :-

getContractCode will need a seperate key-value db implementation