WebSession: disable ORCID login

* Disables ORCID login by removing the string 'orcid' from variable
  CFG_OAUTH2_PROVIDERS in file invenio.conf. (closes #1667)

* Creates a regression test into file websession_regression_tests.py
  that checks if the login page has any kind of openid, oauth1 or
  oauth2 login and fails if so.

* Changes a typo in access_control_config.py and removes the
  consumer_key and consumer_secret value from orcid entry in the
  CFG_OAUTH2_CONFIGURATIONS dictionary.

Signed-off-by: Petros Ioannidis <petros.ioannidis@cern.ch>
Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>