Replace keystone auth_* options with identity_uri

Replaced [keystone_authtoken] auth_* options with identity_uri
option. This patch supersedes #125847 and no longer conflicts
with #120332.

Change-Id: I81cd29b5bb0d75ced2f319aa1438774a3b133c0a
Co-Authored-By: Matt Kassawara <mkassawara@gmail.com>
Merge "Replace keystone auth_* options with identity_uri"