Logout as function instead of router link.

[nonsintetic]

Is your feature request related to a problem? Please describe.
Logging out when using JWT-based autnentication isn't done via a request to the API. Currently the App Bar only supports setting a router link for logout.

Describe the solution you'd like
Logout button should support calling a function or emit an event so you can just implement your own logic.

Additional context
I've solved it by creating a copy of the original component in my source and modifying it, but it won't benefit from any updates that way.