Refactor role list subcommand for identity v3 api

Currently parts of user list and group list command are actually
functioning as role listing, which is quite counter intuitive and
misleading.

This refactor change move role related logic to a single place of role
list command. It now allows role grants listing for user/group +
domain/project combinations.

If no user or group specified, it will list all roles in the system,
which is the default behaviour.

Change-Id: I4ced6df4b76f018d01000d28b4281ad9f252ffcc
Change the token verb to issue/revoke

Change the token verb to issue/revoke as documented in:

https://wiki.openstack.org/wiki/OpenStackClient/Commands#token
https://wiki.openstack.org/wiki/OpenStackClient/Commands#Actions

Change-Id: I44f77f98ad3269c4f2149301c204804dcb75ac81
Merge "Change the token verb to issue/revoke"
Merge "Refactor role list subcommand for identity v3 api"
Complete Identity v3 list command filters

Complete the 'group list' and 'user list' filter options following
the refactor in https://review.openstack.org/69878

Change-Id: Ib4af417c56d4f7da4b88852f191af615cc7fa2ec
Add basic timing support

Add support for novaclient's --timings option.  Due to the transition
to cliff for all data output a psuedo-command Timings is created
to handle output formatting.

TODO:
* extract format and colums options from previous command so
  we can not hard-code '-f table'

Change-Id: I7f1076b7a250fba6a8b24b2ae9353a7f51b792b2
Merge branch 'v3-group-user-list' into dt-test
Merge branch 'new-session' into dt-test
Merge branch 'identity-ec2-tests' into dt-test