Refactor GUI logging to use message claims
Refactor GUI logging to use message claims

We were incorrectly retrieving messages from the logging Zaqar queue.
Each time we ran the workflow, only ten messages were retrieved.

Running the workflow a second time would produce the same logging file
because contrary to what I had thought before, the `queue_messages`
action doesn't "pop" the messages from the queue.

The proper way of using Zaqar is by claiming messages.  Each consumer
claims some messages.  We ask Zaqar for messages, and it gives them to
us.  Those messages are now ours and we can process them.  No other
consumer can touch them.  Once we're done processing them, we have to
manually delete those messages using the previously acquired IDs.
Again, there is no way to request a large number of messages from the
queue so we have to resort to calling `get_messages` recursively until
we run out of messages.

Change-Id: Ie8d1762b3c61ff96ef8b4d32e15e758ef2f618d3
Closes-Bug: 1733633

openstack/tripleo-common,openstack/tripleo-common