WIP oauthclient/accounts: permanent login support

* Sets session.permanent when then user marks 'remember me'.

* Allows configuration of oauth login to set if session should
  be permanent.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
With the approach below of ``` OAUTHCLIENT_SESSION_PERMANENT_LOGIN``` being a dict we allow per client configuration. Should be good