rgw/qa: Add QA suite for Keystone service token

rgw/qa: Add QA suite for Keystone service token

This adds a QA suite  for the service token auth in
RGW. The suite runs a workunit that is a bash script
that spawns a fake Keystone server which is then used
as an auth backend for RGW to test the feature.

A python script is then executed that runs a battery
of tests against RadosGW which talks to the fake Keystone
server running in the background.

Signed-off-by: Tobias Urdin <tobias.urdin@binero.com>