Update avatar name after login

[Terreii]

Is your feature request related to a problem? Please describe.
SL now supports changing names. This change is never reflected in Andromeda.

Describe the solution you'd like
When a user logs with his avatar in, check if the saved name matches the name in the login result. If not update it.

Describe alternatives you've considered
Add a manual name change capability.

Additional context
Users can still use the old names to login.
The avatarIdentifier should probably be changed into the Avatar UUID. Which is also returned by login.