feat: Add functions for recommended labels

[siegfriedweber]

Description

Add functions for recommended labels to v2::kvp::label

The functions use specific types, e.g. ClusterName and ProductName, and are infallible.

Examples:

• chore: Remove role and role group labels where they don't apply airflow-operator#838
  only simple changes, but a lot of them
• Remove the product version label from PersistentVolumeClaims opensearch-operator#171
  only few changes, thanks to the contexts RoleBuilder and RoleGroupBuilder provide

Part of stackabletech/internal-issues#167

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added

[adwk67]

LGTM