fix: GitHub Actions improvements

[mook-as]

Description

Various small CI changes to make running tests more stable; see commits for details.

Cloud Provider Changes

• Skip AKS steps on GKE, etc.
• Bump on GKE cluster size, and use non-preempt for CI.
  • They should be cleaned up correctly by the scheduler workflow, so there's less pressure to keep things cheap in case they get orphaned
• Set up the GKE config directory (the way it is set it catapult), so that kubectl can automatically refresh the access token if a build takes a long time (e.g. running CATS).

Workflow Changes

• The actions need to run against the PR branch, still, so that it checks out the correct source to test against.
• Move the config values generation to a shell script, because it was rather unwieldy
  • Various changes to bring it up to date
• Add timeouts to most steps, so we don't get stuck runs taking too long that would never succeed.
• Fix interaction with how we determine if we're running Eirini
• Wait for DNS to be set up before running tests, as that can take a long time if there are too many entries.
• Retry smoke tests if it fails; it appears that some clusters can fail the first run, for unknown reasons.
• Don't try to get logs if everything succeeded; that can take ~20 minutes (due to the size), which is better spent running tests for the next PR.

Motivation and Context

Part of #1144 in trying to move our CI to GitHub Actions.

This PR is not sufficient for parity; we will still need to look at:

• [ ] brain tests (this blocks closing #1144)
• [ ] upgrade tests (#1147)
• [ ] internetless (#1148)
• [ ] ccdb rotation

How Has This Been Tested?

Been running on my GitHub fork for a few days (manually triggered); it seems to have gotten to a point where most runs succeed now. The last test run (of the whole thing, complete with internal PR) was https://github.com/mook-as/kubecf/actions/runs/369237207.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code has security implications.
  • Need to ensure that people don't run CI until the code has been reviewed.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

[mook-as]

Rebased to drop the two changes mentioned, we can do them separately if desired.