Improve deployment script comments, structure and options
Improve deployment script comments, structure and options

This patch adds several comments to describe the actions taken
in the script, then also provides flexibility for deployments
through the setting of environment variables prior to running
the script:

- ADMIN_PASSWORD can be set and will be used when building an
  AIO for the Admin Keystone account and for the Kibana account
- DEPLOY_AIO can be set to "yes" to deploy an AIO
- DEPLOY_HAPROXY can be set to "yes" to deploy haproxy. This will
  be done automatically when building an AIO.
- DEPLOY_ELK can be set to "no" to skip building the ELK stack
- DEPLOY_MAAS can be set to "no" to skip the MAAS deployment and
  configuration. This will be done automatically when building
  an AIO.

galstrom21/rpc-openstack,cfarquhar/rpc-openstack,hughsaunders/rpc-openstack,miguelgrinberg/rpc-openstack,darrenchan/rpc-openstack,darrenchan/rpc-openstack,git-harry/rpc-openstack,claco/rpc-openstack,mattt416/rpc-openstack,prometheanfire/rpc-openstack,claco/rpc-openstack,jpmontez/rpc-openstack,nrb/rpc-openstack,cloudnull/rpc-openstack,jpmontez/rpc-openstack,darrenchan/rpc-openstack,prometheanfire/rpc-openstack,hughsaunders/rpc-openstack,busterswt/rpc-openstack,robb-romans/rpc-openstack,git-harry/rpc-openstack,BjoernT/rpc-openstack,byronmccollum/rpc-openstack,sigmavirus24/rpc-openstack,mancdaz/rpc-openstack,sigmavirus24/rpc-openstack,robb-romans/rpc-openstack,busterswt/rpc-openstack,nrb/rpc-openstack,galstrom21/rpc-openstack,sigmavirus24/rpc-openstack,mattt416/rpc-openstack,darrenchan/rpc-openstack,stevelle/rpc-openstack,rcbops/rpc-openstack,xeregin/rpc-openstack,sigmavirus24/rpc-openstack,major/rpc-openstack,miguelgrinberg/rpc-openstack,jacobwagner/rpc-openstack,jacobwagner/rpc-openstack,stevelle/rpc-openstack,andymcc/rpc-openstack,cloudnull/rpc-openstack,shannonmitchell/rpc-openstack,cfarquhar/rpc-openstack,andymcc/rpc-openstack,busterswt/rpc-openstack,claco/rpc-openstack,xeregin/rpc-openstack,xeregin/rpc-openstack,byronmccollum/rpc-openstack,miguelgrinberg/rpc-openstack,xeregin/rpc-openstack,rcbops/rpc-openstack,BjoernT/rpc-openstack,mancdaz/rpc-openstack,shannonmitchell/rpc-openstack,stevelle/rpc-openstack,nrb/rpc-openstack,major/rpc-openstack,andymcc/rpc-openstack,byronmccollum/rpc-openstack,mattt416/rpc-openstack,jpmontez/rpc-openstack