Helm chart improvements

[dnskr]

Why are the changes needed?

The changes are needed to improve helm chart usability.
The PR introduces a few enhancements (one per commit) to make Kyuubi helm chart more friendly to be used.

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible

• Add screenshots for manual tests if appropriate

• Run test locally before make a pull request

[pan3793]

@dnskr thanks for your effort, it's awesome to make the commit history so clear, but if we directly merge it(our merge tool forcibly uses squash), commit history will be lost, would you mind opening PR one by one?

[ulysses-you]

cc @hddong

[ulysses-you]

thanks, merging to master

[dnskr]

@dnskr thanks for your effort, it's awesome to make the commit history so clear, but if we directly merge it(our merge tool forcibly uses squash), commit history will be lost, would you mind opening PR one by one?

@pan3793 I created several commits just to make review process easier. Squashed commit contains all commit messages, so looks good for me. For next PRs I'll do it more granular (one change per PR).

[pan3793]

Thanks @dnskr