Added behaviour and model for first config drive openstack metadata

* Added Model
* Added client calling deserialization
* Added missing import and PEP8 issues fixed
* Fixed issues after review and added ec metadata function
* Added create config drive behaviour
* Fixes issues after Daryl review
* Renaming cd to config_drive and models
* Fixing issues after John review
* Added Files model and fixing typo

Change-Id: Idfc8907bed96041b85a816e3ecf34cbfe00d1e34
Merge "Added behaviour and model for first config drive openstack metadata"