Automatic merge from submit-queue (batch tested with PRs 63593, 63539). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Refactor cachingSecretManager
I have a POC of watch-based implementation of SecretManager in https://github.com/kubernetes/kubernetes/pull/63461
This is an initial refactoring that would make that change easier.
@yujuhong - if you're fine with this PR, I will do the same for configmaps in the follow up PR.