visually distinguish multiple public-repo

[duncdrum]

Is your feature request related to a problem? Please describe.
package-service can hold multiple instances of public repo which are queried and displayed by package-manager. This is useful when example an app hosts data packages in a non-default repo, but would like other apps to be upgraded and installed from the default repo. Currently all available packages appear in a single list, with no visual clues about their source.

Describe the solution you'd like
Package manager should open separate tabs for each public-repo instance that it connects to. This way users would know where the apps they are offered originate from.

Describe alternatives you've considered
Color could also indicate separate origins, but tabs have the advantage that large repos don't clutter the single list view that is there now .

Additional context
see eXist-db/existdb-packageservice#17