Add PVC permissions to cluster role in chart

[ccremer]

Summary

• Follow-up of #88
• Adds the necessary permissions to perform PVC changes to the operator's SA

Checklist

• [x] 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
• [x] PR contains the label area:chart
• [x] PR contains the chart label, e.g. chart:provider-postgresql
• [x] Variables are documented in the values.yaml using the format required by Helm-Docs.
• [x] Chart Version bumped if immediate release after merging is planned
• [x] I have run make chart-docs
• [x] Link this PR to related code release or other issues.

[ccremer]

Branch currently is based on #88 , should be rebased after merge. Please review only the files in charts/*