astakos: Introduce `related`, `active` mode in projects list api call

Related mode returns all projects user owns or is has a related membership to.
Active mode returns available public/active projects.
astakos: Improve membership status messages
astakos: Proper project filtering in project list/join views

- In `my projects` view only owned or projects the user is associated with a
  membership get listed.
- In `join project` view list all public/active projects.