Better name for stored password
Currently the name for the stored password is "fractal". This should be changed to something like "Matrix password for <user_id> (Fractal)" so that:
- a search for Matrix, the username or server in the keyring yields results,
- we can eventually store credentials for more than one account.
I’m actually not even sure "Fractal" should be in the label at all. Can a stored secret eventually be reused by another application? It would worth checking what the best practices for this are.