LL-832 OpenID connect working.

This requires additional setup on SSS configuration file side
(authType should be set to oidc; plus some additional configuration of
endpoints within i5CloudConf; the latter should also be enabled). The
code is relatively clean and fully functional, the last issue to resolve
would be to display some ajaxLoader for the user and prevent login form
resubmission (if that is needed).
LL-832 #close Added check to prevent form resubmission.

The check for form resubmission prevention will not let user resubmit
the form if the authentication call is in progress. Not using ajaxLoader
as an indicator, the submit buttons are just disabled.
Merge pull request #1 from learning-layers/feature/LL-832

Feature/ll 832