Allow imagePullSecrets configurable on operator Deployment

[ifalex]

Is your feature request related to a problem? Please describe.
Deployment for kanister-operator is quite limited in options, therefore it fails under many kube-score/kube-linter tests.
Allowing more options to the deployment file would benefit from robustness perspective and best practices around helm chart creation.
To list a few:

• imagePullSecrets
• containerSecurityContext
• podSecurityContext
• affinity
• pdb (although not related to the deployment template file, related to the PDB object missing)
• deployment strategy

Describe the solution you'd like
Improve Deployment/Helm chart to make kanister-operator helm chart a more production ready option (currently won't work on Openshift for example)

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Environment
Kubernetes Version/Provider: ...
Storage Provider: ...
Cluster Size (#nodes): ...
Data Size: ...

Additional context
Add any other context or screenshots about the feature request here.

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[hairyhum]

Hi @ifalex, thanks for posting that. Can you please clarify if you're not able to use kanister without these? Do you have a workaround? If not, please let us know.

[ifalex]

Hi @hairyhum. There are some scenarios where you want to use imagePullSecrets for air gap environments with private registry and authentication. Also this is a best practice in ecosystem so allowing this setting could improve the value of the chart delivered.
There's no workaround unfortunately, had to fork the repo and patch on it.

[hairyhum]

Can you please share your changes and/or tests you use?

[ifalex]

Sure. Will do.