syncsets: tracking issue for sync set proposal

[acpana]

I'm going to use this issue to keep track of some conversations and clean up tasks that are being generated out of the sync set proposal implementation.

Tasks deferred from https://github.com/open-policy-agent/gatekeeper/pull/2852:

• test, style: https://github.com/open-policy-agent/gatekeeper/pull/2852#discussion_r1284757991 : captured in https://github.com/open-policy-agent/gatekeeper/issues/3010
• test, style: https://github.com/open-policy-agent/gatekeeper/pull/2852#discussion_r1284759581

Refactors:

• ~with the CacheManager from https://github.com/open-policy-agent/gatekeeper/pull/2852, a lot of the dep Injectors for config_c are redundant. Let's take a pass and clean them all up~
  • ~indeed, many of the adder's funcs aren't even implemented anymore; can simplify the interfaces maybe~ done as part of https://github.com/open-policy-agent/gatekeeper/pull/2991
• ~AuditFromCache lister requires us to keep a watchSet in the dep for now. Let's revisit that decision. Audit could call out to CM somehow to get the watchSet or answer the question of "what is in the informer cache".~ implemented as part of #2852

Tasks to think about:

• need to update readiness tracker code to deal with sync sets when adding controller
• ~if parser package is moved, this might need an update https://github.com/open-policy-agent/gatekeeper-library/pull/367~ done as part of https://github.com/open-policy-agent/gatekeeper-library/pull/396

[ritazh]

SyncSet Alpha blockers:

• doc https://github.com/open-policy-agent/gatekeeper/pull/3202

SyncSet Beta blockers:

• Still needs status byPod reporting for SyncSet