Enhancement: Customizable profile menu

[hasansezertasan]

Is your feature request related to a problem? Please describe.
The profile menu has only one button: logout. I'm proposing to implement a way to extend this menu from the python side. Maybe a hook like auth_provider. profile_menu could have a bunch of items in it and we could define the functionality with expose feature that I proposed in #389

Additional context
I'm planning to do some work on this, wdyt about this feature @jowilf?

[hasansezertasan]

I reconsidered this and I don't think expose logic is not a must for this but BaseAdmin class might have a parameter called profile_menu and accept Link instances.