No longer needs babel, but requries an alpha version of the typescript plugin
for eslint 8 support

We now enable it by default for everyone. The plan is to load the API
user instead and not the person as a next step. This api should work
even for users that don't have a person associated.

Instead of using the namespace which is hardcoded we use the tag name that was
used to register the element (or the "real" tag name in case of a scoped element).

This way if AppShell is regsitered as "dbp-some-app" it can still be overriden by
specifying "dbp-some-app" in the overrides object.

We use i18n.languages in the app-shell to see which languages are available
but this only contains a list of languages it will search in (means, currently
set language, default one and all fallbacks).

We can just set all languages we know as last fallback, so i18n.languages
always contains all languages.

A bit hacky...

Allow globally overriding slots in the light dom of components and use it to override the auth-info slot in the Nextcloud file picker

This is a bug, but the mixin just ignored undefined here.
The next version will be stricter and raises an error in this case.