Drop Supports' unsupports variable

[kbrock]

Before

• Determine supports? from the unsupported_reason hash. It will return a true, false, String reason, or block.
• Call block if necessary and store the result in unsupported hash.
• We change the unsupported hash every time supports?(:feature) and unsupported_reason(:feature) is called.
• This is not thread-safe.

After

• Determine supports? from the unsupported_reason hash.
• Call block if necessary
• return the result

Advantages

• thread safe
• less code (in the rb file)
• fewer assignments (less code running and fewer operations)

Requirements

Depends upon:

• Drop supports_feature? methods #22883
  • supports :feature returns a String - see dependencies for above
• Fix supports_helper stub_supports to handle unsupported_reason #22976 FIRST COMMIT
  • Use standard SupportsFeatureMixin manageiq-api#1257
  • stub the proper class for stub_supports manageiq-providers-vmware#907
• drop stub_supports :supports manageiq-ui-classic#9152
• fix spec for supports_feature change manageiq-providers-openstack#880

[kbrock]

update:

• rebased (fixed unmergable)
• reduced changes in check_supports

[kbrock]

update:

• rebase (fix merge conflicts)

[kbrock]

@miq-bot cross-repo-test /all

[kbrock]

@Fryguy looks like this passed cross repo tests

[kbrock]

update:

• rebased

update:

• stub_supports is only passed a reason
• stub_supports feature is required

... kicking cross repo

[kbrock]

WIP: This is working and green. Just waiting on #22976

[kbrock]

up-wip: still waiting on #22976 - just un-WIPing to show this is good to go

[miq-bot]

Checked commits kbrock/manageiq@89457da~...f791e24 with ruby 2.7.8, rubocop 1.56.3, haml-lint 0.51.0, and yamllint
7 files checked, 0 offenses detected
Everything looks fine. 🍪

[kbrock]

@Fryguy anything special to push this forward? let me know if you want me to split into 2 PRs (for each commit)