Provide a way to add favorites for just the current user/namespace via Settings page

[isc-tleavitt]

It would be great to have a button in Settings to add the favorites links for the current user and namespace. This is especially relevant for environments like Health Connect Cloud where new users and namespaces will be added after git-source-control is installed. Note: implementation will probably require role escalation via a Z* / IRISSYS class (preferred) or privileged routine application.

This is related to #468 and could make sense to implement at the same time, as we could also use this button to clean up / correct favorites links for the current user.