Adds quota usage support for the V3 API

Adds the ability to do a detailed query from the
os-quota-sets V3 API extension. This was an interface
added in V3 to allow for the querying of current quota
usage. Adds a shell command quota-usage which
uses this interface to show current quota usage as well
as the limit.

The absolute limits response was removed from
the limits extension in a9e29b7e9fbe14ab42f24802a6d2a457a6317ba3
and so the corresponding novaclient command is also removed.
The "quota-show-usage" command now shows the same information.

Differences between the V2 and V3 API are described here:
https://wiki.openstack.org/wiki/NovaAPIv2tov3

Partially implements blueprint v3-api

Change-Id: I5db72d42120f4ad7a86fbfce20382988f6bbf5d3
Merge "Adds quota usage support for the V3 API"