This will help specific deployments that need to do something custom here such
as redirect the user or call some API after Element has logged out and cleared
storage.
Fixes https://github.com/vector-im/element-web/issues/15745
This was surprisingly easy given the number of errors I remember last time, but here it is. This also includes an over-engineered VisibilityProvider with the intention that it'll get used in the future for things like Spaces and other X as Rooms stuff.
The "remember my selection" option wasn't working because the `missing` set still included the approved permission. Solution: remove it from `missing`.
The customisation point is to allow forks to change which widgets get which additional capabilities dependent on their own rules.
This adds various customisations point in the app for security related
decisions. By default, these do nothing, but would be customised at the
app level via module replacement (so that no changes are needed here in the
SDK).
Fixes https://github.com/vector-im/element-web/issues/15350
