Change-Id: I1ed2983cf574ebd565eeac4f8199fbc3a2e29c8e

The current identity role list command (both v2 and v3) is
overloaded with listing roles as well as assignments (if you
provide user, group, project or domain options). This is in
addition to the v3 assignment list command designed for this
purpose.

This overloading complicates the fact that roles can now be
domain specific (i.e. have a domain attribute), so the
command 'role list --domain <domain-name' will soon become
ambigious (this is in a follow on patch).

This patch:

- Adds a v2 assignments list, with support for pulling the
user and project from the auth credentials
- For comapability, adds the same auth support to the
existing v3 assignments list
- Deprecates the use of role list and user role list to list
assignments

Change-Id: I65bafdef4f8c89e863dab101369d0d629fa818b8
Partial-Bug: 1605774

if there are more than one services be found with one
name, a NoUniqueMatch exception should be raised but
we can see a NotFound Exception raised instead. It is
because in "find_service()", we use "find_resource()"
first, if "find_resource()" return a exception, we just
think it is a NotFound Exception and continue to find
by type but ignore a NoUniqueMatch exception of
"find_resource()". This patch refactor the "find_service()"
method to solve this problem.

Change-Id: Id4619092c57f276ae0698c89df0d5503b7423a4e
Co-Authored-By: Huanxuan Ao <huanxuan.ao@easystack.cn>
Closes-Bug:#1597296

Update remaining commands:role, service, user, token.

Change-Id: I06eed60dd2f312bad6076c78b53cd07bcd4cd55c
Partially-Implements: blueprint refactor-identity-unit-test

Commands are "ec2 credentials delete", "service delete", "endpoint delete".
Also update their unit tests and functional tests.

Partial-Bug: #1592906
Change-Id: I1a0b7160b803a523646d09d030e6f112c81c4c24

Clean up fakes.py , use FakeCatalog, FakeProject, FakeService,
FakeEndpoint, FakeRole classes instead, also update their unit tests.

Change-Id: I510d175ec194165b0595ebd430e8cc596d363587
Partially-Implements: blueprint refactor-identity-unit-test

Also update its unit tests.

Change-Id: I82b90658b0d4247cdc9a650f14aceda640a32059
Partial-bug: #1588588

Use osc-lib directly for utils.

Leave openstackclient.common.utils for deprecation period.

Change-Id: I5bd9579abc4e07f45219ccd0565626e6667472f7

Use osc-lib directly for exceptions.

Leave openstackclient.common.exceptions for deprecation period.

Change-Id: Iea3e862302372e1b31ccd27f69db59b4953ca828