[Chore]: Migrate eirini pipelines to the korifi concourse

[georgethebeatle]

Background

Right now we have to maintain two concourse instances - one for korifi and one for eirini. What's more eirini's CI has a way too big resource allocation for the occasional usage it gets. It could easily do with just one cluster for all test runs.

Action to take

• Migrate all eirini-controller pipelines to the korifi concourse.
• Make sure all tests run against the same cluster, this is what we currently do in korifi
• Tear down unneeded eirini infrastructure.
• Tear down all legacy eirini pipelines and their allocated resources.

Impact

Reducing the cost of mainainance of our CI

Dev Notes

No response

[georgethebeatle]

We did move all relevant eirini pipelines to the korifi concourse instance under the zzz_eirini team. Leaving that overnight to see how it behaves before we proceed with deallocation of the eirini concourse instance