Add Image v2 create command

* Add v2 'image create'
* Re-vamp v1 'image create' to correspond
* Tests for v1 and v2 'image create'
* Fix Compute 'server image create tests'

Change-Id: I990dd84bf1a0cfeb368089adbea4010391647701
Merge branch 'identity-ec2-tests' into dt-test