Public organization mediafiles

[Elblinator]

closes #3794

Needs
OpenSlides/openslides-backend#2563
OpenSlides/openslides-meta#146
OpenSlides/openslides-autoupdate-service#1000

[Elblinator]

Still missing

• the items in public folders need to be displayed on the meeting Level (currently only the root folder is displayed
• canAccess() needs to be fixed in Order to exchange getViewModelUnsafe() with getViewModel() (mediafile-repository.service.ts -> getMeetingMediafile() -> getViewModelUnsafe -> canAccess() )
• Editing of the Title should be disable on MeetingLevel (currently possible via edit dialog)
• Deleting and moving of public files should be prohibited (currently possible with mutiselect and the actions in the breadcrumb
• when moving a not public mediafile public folders should not be selectable
• Publizising a mediafile (including folder) does not show the mediafile in a Meeting (info goes through via subscription though) -> display of publizised mediafiles needs to be fixed

Orga-Level:

• The publizise dialog should change wording dependent on published_to_meetings_in_organization_id
• Deleting public files should show the appropriate information (adta is used somewhere)
• Moving a file into a public folder should show a warning that it will be public
• Moving a file out of a public folder should show a warning that it won't be public anymore