Multi Tennancy

[vabene1111]

add support to be in more than one space.

basic options

1. "switcher" where the users chooses which space is active and all other logic remains the same as switching is done on the middleware level
2. "transparent" tennancy is transparent to the users and all content is shown from all member spaces

option 1 is chooses as its much simpler to implement, poses less security risks and can also be used as the foundation to implement option 2 in the future (there is close to 0 extra work when implementing option 1 first, just the switcher).

• add model for space membership
• migrate user permission to space permission
• rewrite permission checks to use space permissions
• add switcher
• space invite
• space creation
• Allow user to create new space while in a space
• permission management / space management page
• add api endpoint to switch active space
• prevent people removing their own admin priviledges from their space or add way to regain those automatically
• add send email to create invite endpoint
• first time setup
• fix share links for logged in users Share link doesn't work between spaces for logged in users #1238
• limit enforcement with invite links
• add tests
  • is_space_owner
  • switch user space permission
  • api: space (no create, view permission)
  • api: userspace (no create, view permission)
  • api: userpsace (cant edit groups)
  • api: invite link
  • space delete only available to owner