Images API v2.0 Image Life Cycle Test.

Implements image life cycle test:
 - added the image CRUD operation test.

Refactors the test:
- removed all env. dependent variables in the test.
- improved the assertions for image update.
- inlined variables to improve readability

Change-Id: Ia12f69eb3c7fa0831f3dc3d0030bc769d736de09
Merge "Images API v2.0 Image Life Cycle Test."