Add Celery

NC-102
Proof of concept of background task running

NC-102
Updated README.rst for Github hosting
Fix bug in authentication docs

nc-44
Update project URL and description
Provide version info at runtime

The version is retrieved from package metadata in production.
For development the version is taken from git.

The version string strives to be compatible with PEP-440

NC-44
Include version into web UI of DRF

NC-44
Add version function for the API call

nc-44
Add docs for retrieving version of NC

nc-44
Implement cloud-project membership managemnt in REST
Expand ?can_manage filter to support CO role
Add a mixin for extra fields exposure
Expose connected clouds and projects in REST
Be consistent with refactoring and names
Address code review comments
Merge branch 'feature/nc-114' into 'develop'

Feature/nc 114 - added cloud permission management, minor fixes
Refactored test_cloud
Cleanup
Allow customer to set project roles
Merge branch 'feature/nc-102' into 'develop'

Feature/nc 102 - celery poc