📖 Add CAPI Provider Operator CAEP

[wfernandes]

What this PR does / why we need it:
This PR adds the management cluster operator CAEP proposal to Cluster API for review.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #3427

/kind proposal

[wfernandes]

@fabriziopandini Feel free to take another look and make changes or add comments where ever you see fit.
Let me know if you'd to update the sequence diagrams to state diagrams if that visualization makes more sense.

Since I'm out next week, if you think we are in a good place to get feedback, feel free to remove the WIP label. Thanks.

[wfernandes]

As per the feedback from the review, I've updated the CAEP with the suggestions.
I'm still thinking about the need or options instead of using SecretName for the variables.

[CecileRobertMichon]

Apologies if I duplicated comments from the google doc, I lost access and wasn't able to review it again

[vincepri]

@wfernandes When you're ready for final review, and approvals, please close out all the open discussions and squash commits

[CecileRobertMichon]

lgtm overall

[wfernandes]

uh...fatal error: concurrent map read and map write in TestPatchTargets.
/retest

[fabriziopandini]

/lgtm
Thanks for the amazing work. Let gets this started!

[fabriziopandini]

/milestone v0.4.0

[wfernandes]

@fabriziopandini Please lgtm it again. I had to fix a markdown linking issue for [secret-name-discussion] and I also updated the lastUpdated field for the proposal to today. (talk about a multi-year proposal! 😄 )

/cc @CecileRobertMichon @vincepri @detiber also looking for a final approval (if y'all approve of course 😄 )

[wfernandes]

/test pull-cluster-api-test-main

[fabriziopandini]

/lgtm

[vincepri]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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[wfernandes]

For future reference, I've created this hackmd doc that has a some of the story break down to accomplish this work.