Image Member Domain Model

This commit is the first layer of image member domain model.
The can_share feature from v1 of glance api will not be
ported to glance v2 api.

Related to bp glance-api-v2-image-sharing

Change-Id: Ibfb790d438efb0f5b29b4786c02f1155962150c5
Merge "Image Member Domain Model"