improve project list / get rid of fetch

[ThomasHalwax]

The local-only version of the project list relies on the very responsive local level db. By introducing replication we added a lot of delay when fetching projects the user is invited to join.

• filtering is extremely slow since every keystroke re-schedules fetch
• handling "live" invitations results in an empty list because replication is undefined

This component should be re-written in order to get rid of these problems.