Automatic merge from submit-queue (batch tested with PRs 68171, 67945, 68233). If you want to cherry-pick this change to another branch, please follow the instructions here: https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md.

Move the CloudControllerManagerConfiguration to an API group in `cmd/`

**What this PR does / why we need it**:
This PR is the last piece of https://github.com/kubernetes/kubernetes/issues/67233.
It moves the `CloudControllerManagerConfiguration` to its own `cloudcontrollermanager.config.k8s.io` config API group, but unlike the other components this API group is "private" (only available in `k8s.io/kubernetes`, which limits consumer base), as it's located entirely in `cmd/` vs a staging repo.
This decision was made for now as we're not sure what the story for the ccm loading ComponentConfig files is, and probably a "real" file-loading ccm will never exist in core, only helper libraries. Eventually the ccm will only be a library in any case, and implementors will/can use the base types the ccm library API group provides. It's probably good to note that there is no practical implication of this change as the ccm **cannot** read ComponentConfig files. Hencec the code move isn't user-facing.

With this change, we're able to remove `pkg/apis/componentconfig`, as this was the last consumer. That is hence done in this PR as well (so the move is easily visible in git, vs first one "big add" then a "big remove"). The only piece of code that was used was the flag helper structs, so I moved them to `pkg/util/flag` that I think makes sense for now.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
ref: kubernetes/community#2354

**Special notes for your reviewer**:

This PR builds on top of (first two commits, marked as `Co-authored by: @stewart-yu`) https://github.com/kubernetes/kubernetes/pull/67689

**Release note**:

```release-note
NONE
```
/assign @liggitt @sttts @thockin @stewart-yu