ci(gha): verify CI stability action

[jakubdyszkiewicz]

Checklist prior to review

Introduce GHA action to check CI stability.
It's this #11589 but without me leaving the laptop running the script.

The action runs every 2h outside of working hours during weekdays (feel free to suggest better hours) and every 2h on the weekends. It adds a commit to PRs with ci/verify-stability label. Additionally, if there is ci/verify-stability-merge-master we merge master.

The use case is that we can have a "long-running" PR with both labels so it checks the stability of the current master branch.

You can also do the same but on a PR. Let's say we introduce a risky change. We can remove a label on our long-running PR and instead put ci/verify-stability on the PR with a risky change.

Potential improvements:

• Instead of every 2h, we could track if the CI run finished and then push another commit to have more runs.
• It does not work with forks. Not sure if it's even possible, because we push commits to the branch we may not have an access to

• Link to relevant issue as well as docs and UI issues --
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as a image registry) and it will work on Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Tests (Unit test, E2E tests, manual test on universal and k8s) --
  • Don't forget ci/ labels to run additional/fewer tests
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label) --