Frontend Integration Permission Management for platforms

Acceptance criteria:

List view:

• not logged in user should only see public platforms
• logged in user should see public and internal platforms as well as her/his own private ones
• sms admins should still see all (will need the user self info endpoint on the sms backend, there was some work already done, but not yet finished)
• deletion should only be possible for admins of a group (internal or public) or for the owner (private)

Detail view:

• same visiblity rules are there for direct access of a platform
• only group members, group admins & the sms admin (internal & public) or the owner are allowed to edit the platform
• only group admins & the sms admin (internal & public) or owners (private) are allowed to delete
• selection of groups & visiblity status in the base form