Mail wizzard triggers on a *.onmicrosoft.com domain and then automatically uses Office365 servers with OpenIDConnect authentication
- access- and refresh-token get acquired with https://outlook.office.com/IMAP.AccessAsUser.All scope
ToDo:
- find out why Microsoft denies access with the returned access-token
- store access-token for its lifetime in the cache
- store refresh-token instead of password, to get a new access-token, if it's expired
--> add OAuth logic to mail client (not just wizard)
