Remove deprecated kubernetes executor configuration fields

Merged Tomasz Maczukin requested to merge remove-deprecated-kubernetes-configuration-fields into master

What does this MR do?

Follows up !391 (merged) and removes deprecated configuration fields for Kubernetes executor.

Why was this MR needed?

With !391 (merged) we've added a way to configure both limits and resources for containers. We've also changed names of configuration fields leaving a fallback mechanism for old names and a deprecation note.

In %v9.0 we're cleaning this up removing previously deprecated fields and the fallback mechanism.

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

  • Documentation created/updated
  • Tests
    • Added for this feature/bug
    • All builds are passing
  • Branch has no merge conflicts with master (if you do - rebase it please)

What are the relevant issue numbers?

Closes #2032 (closed)