Add Logout URL Field to OIDC Settings

[mel-64]

hey
I'd be very useful if there were a field in the OIDC settings to set a custom logout URL.
This would prevent 'login-loops' where if one logs out and 'bypass local login' is activated they're logged in instantly again.
That way, it would be possible to redirect to a OIDC providers logout page instead (attached screenshot).