GitLab

* new model Service
* new management commands for handling the services
* remove ASTAKOS_CLOUD_SERVICES setting
* change get_services API call to return
the Service objects
* separate admin from service API calls
* introduce send_feedback service API call

Refs: #2413

Provide api calls for permitting helpdesk users to access user information by user email and by username

Refs: #2414

Refs: #2415

if ASTAKOS_COOKIE is set and the request user is not authenticated (sessionid cookie has expired or deleted), authenticate and login the user

Refs: #2291

Refs: #2363

remove is_accepted & date_accepted Invitation fields (substituted by consumed & date_consumed reps.)

snf-manage commands: do not send activation email in active users & do not allow inactive users to send invitations

shibboleth signup form throughs validation error in case of an inactive account with conflicting email

 
keyword argument request is not passed in PasswordResetForm.save(), use BASEURL setting instead of building it from the request

Refs: #2291

* unique email and is_active combination (use django model validation)
* use different template for rendering shibboleth signup form
* do not show groups in profile page
* do not show provider in third-party signup forms

Refs: #2167

Refs: #2291