added AssetEnvType model class + used it in device & added to admin view
better names for AssetEnvType & added migration file
added new table ServiceCatalog & used it in discovery.device
flake8 ready ;P
service_catalog inherited from cmdb.ci
better import
added utils files with object factories (for tests) & device lookups
rm unused lookup DeviceEnvironment
added factory-boy to setup.py
flake8 ready
better docstring
review impr.
Merge pull request #992 from xliiv/ser-env-fields

service & environment fields