Add docs job for os-cloud-config

Since os-cloud-config includes documentation, we should take the
first step of improving it and putting up in an easily accessible
place. To that end, add a os-cloud-config-docs job to build and
publish the docs.

Change-Id: Ib008e5d6f10725196dcc5747c6f1eca5ba7fff7f
Closes-Bug: #1317749
Merge "Add docs job for os-cloud-config"