Integrate FireStore to persists user projects

[d3lm]

Currently, projects only live within local storage and the user's machine. They are not not persisted in a DB.

It would be cool if we integrated FireStore to synchronize the user's projects to a DB so that they are available on other machines as well.

This means we would also need Firebase authentication and whenever an action was dispatched that updated the one of the user's projects, we'd sync it with FireStore. For this we could use @ngrx/effects and encapsulate the side effects related to synchronization between the client and the DB.