Add schema for compute 2.45 microversion

Compute microversion 2.45 changed the response
of create image and create backup APIs.

create image schema already covered
- https://github.com/openstack/tempest/blob/fec2c93cdcc14ad08d0a35136ee287525e7a4879/tempest/lib/api_schema/response/compute/v2_45/images.py

This patch adds the schema for create backup API.

Partially Implements: blueprint fix-microversion-gap

Change-Id: Icfeec8957c58472e7f176680d48745b5c5350b55
24 files changed