feat: introduce new retain harbor resources labels and deprecate old ones

[shreddedbacon]

Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for changelog and subsystem label(s) applied

This introduces new retaining labels that can be added to the harbor secret, or the namespace, that will inform the deletion handler to not clean up resources in harbor when a namespace is deleted.

The following labels can now be added to the namespace or the internal registry secret that Lagoon uses to prevent resources being deleted in harbor when a namespace is deleted in kubernetes. This would mostly used if you're migrating an environment between two clusters that may share the same harbor. If they're different harbors, then you probably don't need to use these at all.

• harbor.lagoon.sh/retain-repositories
• harbor.lagoon.sh/retain-robotaccount

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These two labels were created for this purpose initially. These labels are now deprecated, and you should use the new ones

• harbor.lagoon.sh/cleanup-repositories
• harbor.lagoon.sh/cleanup-robotaccount