Catalyst backend: support all extensions and skins repositories

Including the atypical VisualEditor/VisualEditor and mediawiki/services/parsoid repos.

design/codex and oojs/ui are still pending.

Also fixed a bug were we were sending the Catalyst API the full list of allowed repositories instead of only the ones selected by the user. This was probably not detected previously because when the preset custom is selected the list of allowed repos is the same as the selected repos. For other presets those two lists differ

Bug: T373604