Refactor env-setup.sh
Refactor env-setup.sh

env-setup.sh got kind of unwieldy and out of sync
with itself. Refactor so we have relatively consistent
package lists, installation checks, etc. for each OS family.
This should be easier to maintain than what we have now
as it's easier to see where additional requirements should
be added.

Change-Id: I8a620a177efd8303bf30ebeb0f6a719a49eedf07
Closes-Bug: #1583803

openstack/bifrost,openstack/bifrost