This commit adds an option for controlling request of compaction to
etcd3 from apiserver. There is a situation that apiserver cannot fully
own its etcd cluster (e.g. sharing it with canal). In such a case,
apiserver should have limited access in terms of etcd's auth
functionality so it don't have a priviledge to issue compaction
requests. It means that the compaction requests should be issued by
other component and apiserver's compaction requests are needless.
For such use cases, this commit adds a new flag
`storagebackend.Config.CompactionInterval`. If the flag is non 0,
apiserver issues the compaction requests like current behaviour (the
default is 5 minutes). If it is 0, apiserver doesn't issue the
requests. It can be configured with a newly added option of apiserver
`--etcd-compaction-interval`.
The first one being RecommendedPluginOrder the second one being DefaultOffPlugins.
In case a cluster-admin did not provide plugin names they will be derived from these fields.
Automatic merge from submit-queue (batch tested with PRs 51134, 51122, 50562, 50971, 51327)
set --audit-log-format default to json
Updates: https://github.com/kubernetes/kubernetes/issues/48561
**Release note**:
```
set --audit-log-format default to json for kube-apiserver
```
