KEP-5229: Asynchronous API calls during scheduling

[macsko]

• One-line PR description: Add KEP-5229

• Issue link: Asynchronous API calls during scheduling #5229

• Other comments:

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[macsko]

/cc @dom4ha @sanposhiho

I have written some possible approaches to these API calls to start the discussion. I will not be visibly active for the next three weeks, but feel free to comment.

[k8s-ci-robot]

@macsko: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-enhancements-test	9272ef0	link	true	/test pull-enhancements-test
pull-enhancements-verify	9272ef0	link	true	/test pull-enhancements-verify

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[macsko]

I feel like queueing API calls might be a good direction long term and probably won't be that hard to implement.

[sanposhiho]

Great summary! I'll take time reading through it and put some comments after that.