Add preliminary instance provisioning for OpenStack

Only positive flow is implemented.
Wait one minute for instance to become ACTIVE,
then conclude it failed to boot.

NC-157
Start, stop and delete actions for Instance

NC-157
Use proper log levels for instance actions logging

NC-157
Celery backend URLs are now configurable in settings.ini
Merge branch 'feature/nc-157' into 'develop'

Some instance related actions, NC-157