Drop unused ProjectPermissionReadSerializer
Switch to whole MiBs for ram and disk in flavor

NC-139
Add OpenStack specific flavor_id field

NC-139
Implement pulling flavors in OpenStackBackend

NC-139
Simplify sync states

There was no need for different pull* and push*
states during sync.

They all are mutually exclusive and nobody really cares
whether a model is being pulled or pushed.

NC-139
Sync flavors on cloud account creation

NC-139
Drop dummy flavors creation

NC-139
Merge branch 'feature/nc-139' of code.opennodecloud.com:nodeconductor/nodeconductor into feature/nc-139
backup schedule test corrected (NC-139)
Merge branch 'feature/nc-139' into 'develop'

Feature/nc 139