Update CI systems to validate and publish section openstack-training

Updated manuals.yaml to reflect the pom.xml location specified
in openstack-training. Also added publisher statement to allow
 openstack-training to show up on docs.openstack.org Updated zuul
 layout.yaml to enable zuul to gate openstack-training.

Change-Id: I2e082a7c02547d76d4df97a5deaecbb3faf86652
Implements: Blueprint training-manuals
Merge "Update CI systems to validate and publish section openstack-training"