[YUNIKORN-2990] Add support for securityContext in the helm charts

[pbacsko]

What is this PR for?

Add support for various securityContext settings in the template.

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/browse/YUNIKORN-2990

How should this be tested?

Screenshots (if appropriate)

Questions:

• - The licenses files need update.
• - There is breaking changes for older versions.
• - It needs documentation.

[wilfred-s]

We should also add the same change to the admission controller deployment.

[wilfred-s]

LGTM +1
leaving open for others to comment on the changes

[josqu4red]

Could defaults be set to match the container images ?

[craigcondit]

The values are meant for overrides. If blank they will already default to the container settings. As YuniKorn doesn't read or write any files, the actual values don't really matter much. However, setting security context is convenient in environments where this is required for policy reasons.

[josqu4red]

Right. I planned to submit this change for policy reasons (but stopped at the Jira step). Good to have it now 👍

[craigcondit]

I personally would rather not encode this (or any other specific values) into the default helm chart. Security context is something each environment policy differs on. It's not possible to construct one that will satisfy every policy. The default values are already secure; this PR simply allows setting them explicitly if required in certain environments.

[josqu4red]

Yes that makes sense.
Aside from this it would have been nice to reuse the values hierarchy (e.g .Values.admissionController.podSecurityContext instead of .Values.admissionPodSecurityContext etc.) don't you think?