Add nri-plugins operator

[fmuyassarov]

Move the operator code from:

1. https://github.com/containers/nri-plugins-operator
2. rbac: operators should not contain permissions to create CRD nri-plugins-operator#3
3. testing: add basic boilter plate for testing operator nri-plugins-operator#4

Also, refactor the nri-plugins so that we can reuse the already existing CRD yamls instead of duplicating them.
There is one thing left to be added, which is image build refactoring. I will add it soon, but the rest is ready for review.

[klihub]

A general comment about the PR... Although this is definitely not a showstopper/biggie, but since we're lifting existing code over from another repository, I wonder if the current PR commit history makes sense for each commit, or if it could be squashed to fewer ones. For instance, cannot we create the operator directly in the final location instead of first adding it in one location then moving it to another ? Also, it looks to me like the first two commits could as well be squashed together.

If I try to take a milky-way perspective at the full set of additions in this PR, it seems to me that a more logical set of commits would be:

1. add operator (commits 1, 2, 5, 6 squashed)
2. add operator bundle for packaging (commits 4, 7 squashed)
3. add operator scorecard testing (commit 3)
4. add/link in documentation for the operator (commit 8)

[klihub]

First commit message has an outdated reference to PluginConfig which I think should be NriPluginDeployment instead.

[klihub]

@fmuyassarov Here is a rewritten history which is not squashed to a single commit and is more along the lines what I've been thinking of: https://github.com/klihub/nri-plugins/tree/devel/plugins-operator

[fmuyassarov]

@klihub @marquiz @askervin @kad PTAL. It is ready now.

[klihub]

@askervin @marquiz @kad PTAL.

[kad]

I don't have any concerns about this PR, except deletion of files under docs/deployment/. Is that expected?

[fmuyassarov]

I don't have any concerns about this PR, except deletion of files under docs/deployment/. Is that expected?

We are not deleting docs but rather re-structuring them to accommodate the operator document. You can also see from the changes lines at the top of the PR.

[kad]

ok. mine bad, didn't notice moving files around. LGTM