feat: Add support for standalone chart labels

[as51340]

Closes #250

[as51340]

Tracking

• Link to Epic/Issue

Standard development

• Update / add chart templates, values, and NOTES.txt as needed
• Run helm lint and helm template locally against the changed chart(s)
• Verify the chart installs and upgrades cleanly on a test cluster

Labels checklist

• Add a docs label (exactly one): docs-changelog-only, docs-needed, or docs-not-needed
• Add at least one component label: memgraph, memgraph-ha, memgraph-lab, or infrastructure
• Add at least one type label: bug, feature, or infrastructure
• Assign the PR to a milestone
  • If not known, set for a later milestone

Documentation checklist

• Write a release note, including added/changed clauses
  • Users can now set custom pod and statefulset labels. #252
  • What has changed? What does it mean for a user? What should a user do with it? [#{{PR_number}}]({{link to the PR}})
• Documentation PR link
  • Is back linked to this development PR