fix(helm): add more customisation options

[t3mi]

What type of PR is this?

• Enhancement / New Feature
• Bug Fix
• Refactor
• Optimization
• Test
• Documentation Update

What this PR does / why we need it:

Adds more customisation options for operator deployment, in particular:

• allow to set custom labels on a deployment/pod level
• allow to change revisionHistoryLimit
• allow to set go runtime env variables or any other env variables
• allow to set additional arguments for the command
• allow to set nodeSelector/priorityClassName/topologySpreadConstraints

Which issue(s) this PR fixes:

Fixes #

Related Issue/PR #

Additional information:

[istio-testing]

Hi @t3mi. Thanks for your PR.

I'm waiting for a istio-ecosystem or istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[fjglira]

/ok-to-test

[t3mi]

/test gencheck