Add files to create worker RPM and get api/db/queue/worker nodes deployed.

As part of building out the Barbican network of nodes, this commit adds files
and configuration to create an RPM package for the Barbican worker nodes. Files
needed to make this work as part of a network of Barbican API, queue, worker
and database nodes are also added.

Change-Id: I87a36b7c09bbd3fec7661ce6adbcbb5b0c6df689