Make deploy-ci-overcloud script configurable

Pulls almost all values in from the json env files. Left alone a few
exceptions that I don't see us actually needing to configure at this
point.

Aside from setting the region name to hp1, this script contains no
hardcoded defaults - it assumes that the hp1 config files will be around
to provide the values for that region.

Change-Id: Ie5876222dbd01e18a7e81aa1c3cb92407b9206ed
Remove deprecated vconfig support

This removes the deprecated vconfig support which I'm not sure
ever worked properly to begin with. The
neutron.ovs.public_interface_raw_device heat metadata parameter
can also be removed since it is no longer used for anything.

Once this lands we should follow up and land a Heat templates
patch to remove the neutron.ovs.public_interface_raw_device
parameter there as well. I've filed this bug to track that:

Partial-bug: #1386910

Change-Id: Ia712d5e5d6de4aa41857b12a8d218dd9ec41be61
Mention dib-utils package in sample instructions

dib-utils has moved to its own package, and needs to be installed as
part of a minimal usage of diskimage-builder

Change-Id: If89c90e312fb9d1babde801eff61b62173b3b27d
Support custom privileges for managed MySQL users

MySQL users can now now 'privilege' property associated with them,
allow for managing users with lower than ALL privileges.

Change-Id: Id647c5f0cf169f9c907cf9e9dfca16e05c796257
Merge "Remove deprecated vconfig support"
Merge "Make deploy-ci-overcloud script configurable"
Merge "Mention dib-utils package in sample instructions"
Merge "Support custom privileges for managed MySQL users"