[feat] Add realtime presence

[drfarrell]

Describe the feature

Make it so that if two users are in the same project they can see eachothers pictures in this upper-right corner.

Users are already able to see inside eachothers projects, they just don't know if someone else is in the same project

[naaa760]

Hello! @drfarrell
I have implemented the realtime presence feature users can now see each other's avatars in the top-right corner when working on the same project together.

Please let me know!