Refactor qos spec unit test with FakeQos class
in volume v1.

Change-Id: Ia76bf41a911457282b293dfaf0af311b1a9194ce

1.Add mutually exclusive options into a mutually
exclusive group.
2.Add "--source-replicated", "--consistency-group",
"--hint" and "multi-attach" options
3.Make --size option to be optional under some cases

Closes-Bug: #1568005
Closes-Bug: #1627913
Implements: bp implement-cinder-features
Co-Authored-By: Roman Vasilets <rvasilets@mirantis.com>
Change-Id: I2c4c3073195d33774e477f4d7f22e383b14b41dd

Add "consistency group" object in volume v2 (v2 only)
and implement "consistency group list" command

Change-Id: Ifa90d97f4b223f9a5b00708cff07fa2c5e2635f0
Implements: bp cinder-command-support
Partial-Bug: #1613964
Co-Authored-By: Sheel Rana <ranasheel2000@gmail.com>

There was not any unit tests for backup commands
in volume v1 so that sometimes some small bugs
maybe ignored, this patch add unit tests for them.

Change-Id: Ic67c1b80243f7b3d15dabd25e4e4a1b1517a8b59

After I found this problem appear in "volume unset",
I checked all the volume command and also found some
same problems. This patch fix them all.
The main reason of we ignored this problem before is
there was not any tests for it. So I add tests for
"nothing unset" for them all to test and aviod this
problem.
Also, I add unit tests for all snapshot commands
in volume v1 by the way in this patch. We will
need more tests to avoid some ignored problem.

Change-Id: I46775f24643d715e168b30785b8b531c0431a55b
Partial-bug: #1588588

Add "volume transfer request show" and
"volume transfer accept" commands in
volume v1 and v2. Also add the unit tests,
docs, release note and functional tests

Implements: bp cinder-command-support
Co-Authored-By: Sheel Rana <ranasheel2000@gmail.com>

Change-Id: I5787fc486b3401307125caa316f517b9c96a95a5

Add "volume backup set" command in volume v2 (v2 only)
to set backup name, description and state

Change-Id: If17e8457db9a4704fb5bb9c75921ed82fd0069cf
Closes-Bug: #1613261

When nothing specified in "volume unset" command, there
will be an error message says that the "--properties"
option is required, it is unusual behaviour, this patch
fix it and also add unit test for it.
Also, this patch add unit test for "volume show" command
by the way.

Change-Id: I5b5d587670acf0af4262b8521292455bf9f60fe5
Partial-bug: #1588588

FakeVolume class has been added in the fake.py in
volume v1, this patch refactors the volume command
unit tests with the FakeVolume class.

Change-Id: Ic3c1a46d5bff9048d0095f5739ae9e5a34ca6b5b