Easee: reauthenticate on failing token refresh

[GrimmiMeloni]

Server side changes deployed by Easee can lead to valid refresh tokens becoming invalid.
The only way out of this situation is to perform a full reauthentication using username and password to get a new set of tokens.
evcc is currently not able to perform this reauthentication and requires a restart when this problem occurs.

This is issue to track development of required changes to perform a reauthentication without restarting evcc.

@andig please assign to me.

[andig]

In 20min im Nightly

[MaxV85]

Ich wollte mich melden und sehe aktuell kein Problem mit der Easee mehr. Genial! Danke euch für das und ich hoffe, erstmal ist jetzt Ruhe an der Easee-Front