Adding qpid support to nova

Moving all qpid parameters under default["openstack"]["compute"]["mq"]["qpid"]
so that other qpid options can be added under it. Rabbit parameters
will be brought under "mq" eventually. Default is "rabbit".
Bumped up the minor version number from 7.1.0 to 7.2.0

Implements: blueprint qpid-activemq-support
Change-Id: Ie40b5a46a07ce12b7220efe9c4021252a1c6a1ce