Make changes for the published orga mediafiles

[luisa-beerboom]

Related issues:
OpenSlides/openslides-client#3794
OpenSlides/openslides-backend#2563

Meta PR
OpenSlides/openslides-meta#146

As a result of this issue, the mediafile model was split in two: mediafile and meeting_mediafile.
The entirety of the changes in the meta PR require the following restrictor changes:

• mediafile:
  • If mediafile/owner_id is the organization, the user should be able to see the mediafile, if
    • mediafile/published_to_meetings_in_organization_id is not None and he is part of any meetings admin group,
    • he can see any of the related meeting_mediafiles,
    • or he fulfils the conditions detailed in the previous version.
  • If mediafile/owner_id is a meeting, the user should be able to see the mediafile, if
    • he can see any of the related meeting_mediafiles. (Note: in this case there should be exactly one meeting_mediafile, unless the database is corrupt)
• meeting_mediafile:
  • The user can see a meeting_mediafile if
    • he is an admin of the meeting.
    • he has projector.can_see and there exists a meeting_mediafile/projection_ids with projection/current_projector_id set.
    • he has mediafile.can_manage.
    • he has mediafile.can_see and either:
      • meeting_mediafile/is_public is true, or
      • he has groups in common with meeting_mediafile/inherited_access_group_ids.
  • Mode A: The user can see the meeting_mediafile
• meeting:
  • New restriction mode E: The user is in any meetings admin group

[luisa-beerboom]

Also required changes for the projection system:
The old mediafile projections have been rewired to the meeting_mediafile.
The slide code for these needs to be changed so that the type name remains as mediafile, but the content_object_id is now expected to be a meeting_mediafile. Therefore to reach the proper mediafile data, the mediafile needs to first be accessed via the meeting_mediafiles mediafile_id, before the content is calculated.

[bastianjoel]

Implemented in #1000