Support setting priority class of operator in Helm chart

[DebakelOrakel]

Summary

Support setting priorityClassName of operator deployment in Helm chart.

Checklist

For Code changes

• Categorize the PR by setting a good title and adding one of the labels:
  bug, enhancement, documentation, change, breaking, dependency
  as they show up in the changelog
• PR contains the label area:operator
• Link this PR to related issues
• I have not made any changes in the charts/ directory.

For Helm Chart changes

• Categorize the PR by setting a good title and adding one of the labels:
  bug, enhancement, documentation, change, breaking, dependency
  as they show up in the changelog
• PR contains the label area:chart
• PR contains the chart label, e.g. chart:k8up
• Variables are documented in the values.yaml using the format required by Helm-Docs.
• Chart Version bumped if immediate release after merging is planned
• I have run make chart-docs
• Link this PR to related code release or other issues.

[TheBigLee]

@DebakelOrakel Please sign your commit for the DCO check to pass.
Also don't forget to run make chart-docs

[DebakelOrakel]

@DebakelOrakel Please sign your commit for the DCO check to pass. Also don't forget to run make chart-docs

Done.