Remove Firebase

[SilkyPants]

This is no longer required - as it was more reliable to hear from the community than checking the dashboard (and then how would it get opened to other devs etc)

[Blaumeise03]

Should be resolved with version 0.3.8, but I am not 100% sure if I have removed firebase from every place. And there are still some dead code/files remaining that are no longer required.