Move remaining schema files into v2_1 directory

After removing v3 schemas, we have only 1 set of schemas for v2 (/v2.1)
APIs but those end up in scattered structure.

Schema files needs to be re arranged into a clean structure. Any
resource schema should be defined in single file for better readability.

This patch move remaining schema files into v2_1 directory and rename
some schemas according to their API.

Partially implements blueprint rearrange-nova-response-schemas

Change-Id: If07f0a929c7085090bcefd4d2d565b896bf438f3
19 files changed