Allow user to delete a package settings entry

[jeremymv2]

We should consider supporting a way for users to delete empty Packages.

If a user wishes to clean out unused Packages from an Origin, they will delete all the Artifacts but then also will likely want to delete the empty Packages so that they don't clutter up their UI.

The Packages entries come from the origin_package_settings table.
The Artifacts reside in the origin_packages table.

Deletion might entail supporting a DELETE operation on the /settings endpoint.

[jeremymv2]

Without this users could potentially be unable to delete an origin that otherwise should be deleteable.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. We value your input and contribution. Please leave a comment if this issue still affects you.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. We value your input and contribution. Please leave a comment if this issue still affects you.