Add goals and docbook-properties.sh script to openstack-training

Added properties injection script docbook-properties.sh statement
added maven goals inserting release path and comments from
pom.xml. The goal of this is to allow openstack-training
to be released to docs.openstack.org/trunk/foo w

Change-Id: If640e533654989e8ac1ed8e0f75b4fb701ffa5f2
Implements: bp/training-manuals
Merge "Add goals and docbook-properties.sh script to openstack-training"