Keystone Authentications Celery task Pull Request

This pull request for openstack - keystone authentication pull request
NOTES
 - Keystone Authentications is implemented.
 - Keystone User Creation task is implemented.
 - These methods do not have test method, because we need to use mock object to test this.
 - We will implement this soon.
 - Openstack Swift method is updated soon (until ~01:00 13. October)