Rework the HOT environment section
Rework the HOT environment section

* Rephrase the descriptions
* Use yaml syntax highlighting
* Reorder the examples
* Comment out the setup of environment server side (this should be moved
  to the admin cloud guide)

Change-Id: I691fd21b38da42c7c1c4fafe9fbd5c4cf7787aeb

Akasurde/openstack-manuals,kairoaraujo/openstack-manuals,openstack/openstack-manuals,Akasurde/openstack-manuals,gongysh2004/openstack-manual,AlekhyaMallina-Vedams/openstack-manuals,potsmaster/openstack-manuals,potsmaster/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,saeki-masaki/openstack-manuals,kairoaraujo/openstack-manuals,saeki-masaki/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,gongysh2004/openstack-manual