Frontend: Repository permissions for campaigns

Created by: eseliger

Related backend work: #10809 (closed)

Implement UI component for HiddenPatch
Implement UI component for HiddenExternalChangeset
Make sure campaign status also shows errored for errors.length === 0 but status === ERRORED
In campaign update diff generator put all hidden{Changesets|Patches} into unmodified tab
CampaignUpdateDiff: Show info box when some changesets won't be updated