fix: allow overriding of application service account

[razvan]

Description

Fixes #616

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[sbernauer]

Nice fix, thanks and thanks for the test!
It would be nice if you could also assert the used ServiceAccount on the created Pods

[razvan]

Nice fix, thanks and thanks for the test! It would be nice if you could also assert the used ServiceAccount on the created Pods

done

[sbernauer]

Thanks! Sorry, I didn't know the assertion would be this complicated...

[razvan]

I had another typo but now ...

--- PASS: kuttl (101.23s) --- PASS: kuttl/harness (0.00s) --- PASS: kuttl/harness/overrides_openshift-false_spark-3.5.6 (99.72s) PASS 

[lfrancke]

Please add a release note snippet in the form "Previously, this went wrong. With this release, this was fixed in the following way."

[razvan]

Release Note

The service account of spark applications can now be overridden with pod overrides.

Previously the application service account was passed as command line argument to spark-submit
and was thus not possible to overwrite with pod overrides for the driver and executors.
This CLI argument has now been moved to the pod templates of the individual roles.