Process annotation marking pod as not safe to evict first

[lauraseidler]

What type of PR is this?

/kind feature

What this PR does / why we need it:

By processing this annotation first, pods that would match also other, subsequent rules (e.g. pods without a controller), will generate the NotSafeToEvictAnnotation instead of e.g. NotReplicated.

This allows marking pods as not safe to evict to change the warning to one that can be more effectively ignored, e.g. for ephemeral build pods that are known to not be backed by a controller, and should not be evicted.

Which issue(s) this PR fixes:

Fixes #5434

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Pods with the "cluster-autoscaler.kubernetes.io/safe-to-evict": "false" annotation will now always report an annotation-related warning message if they block scale-down (where previously they might've reported e.g. a message about not being replicated).

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: lauraseidler / name: Laura Seidler (75b5f2b)

[k8s-ci-robot]

Welcome @lauraseidler!

It looks like this is your first PR to kubernetes/autoscaler 🎉. Please refer to our pull request process documentation to help your PR have a smooth ride to approval.

You will be prompted by a bot to use commands during the review process. Do not be afraid to follow the prompts! It is okay to experiment. Here is the bot commands documentation.

You can also check if kubernetes/autoscaler has its own contribution guidelines.

You may want to refer to our testing guide if you run into trouble with your tests not passing.

If you are having difficulty getting your pull request seen, please follow the recommended escalation practices. Also, for tips and tricks in the contribution process you may want to read the Kubernetes contributor cheat sheet. We want to make sure your contribution gets all the attention it needs!

Thank you, and welcome to Kubernetes. 😃

[towca]

The change is slightly user-facing, but the warnings are not generally expected to be a stable interface anyway. If you want, you can edit the description to include something like 'Pods with the "cluster-autoscaler.kubernetes.io/safe-to-evict": "true" annotation will now always report an annotation-related warning message if they block scale-down (where previously they might've reported e.g. a message about not being replicated).'

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lauraseidler, towca

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• cluster-autoscaler/OWNERS [towca]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment