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 #2852:

• test, style: feat: support multiple sync sources #2852 (comment) : captured in refactor:test: introduce ConfigMap fake #3010
• test, style: feat: support multiple sync sources #2852 (comment)

Refactors:

• with the CacheManager from feat: support multiple sync sources #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 refactor: adder interface, rename data client #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 feat: support multiple sync sources #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 feat: use gatekeeper parser for require-sync gatekeeper-library#367 done as part of chore: require-sync gk update gatekeeper-library#396

[ritazh]

SyncSet Alpha blockers:

• doc docs: syncset docs #3202

SyncSet Beta blockers:

• Still needs status byPod reporting for SyncSet