Add keystone service metadata for v3 client

V3 resources structure/resource relation are completely
different than in v2. This patch introduce metadata for
v3 resources stored in:

  * keystone/client/v3/services/*

The new module/state in keystone to work with v3 only was introduced
by https://gerrit.mcp.mirantis.net/19529.

The change is fully backward compatible, as new resources will be
used only when keystone:client:resources:v3:enabled is set explicitly
to True.

Change-Id: I0f0e53dda29572987f221438394083590bb6a6e5
Related-Prod: PROD-19148
51 files changed