Convert AS distribution into a suitable layered product/project "distribution base"

See https://community.jboss.org/docs/DOC-47927 for a discussion of the concepts involved. This task is to convert the AS 7 distribution and boot process such that the AS is suitable for use as the "distribution base" as discussed in that document.

This task does not include things like the patching tool or installers discussed on that wiki. The intent is solely to make the AS distribution suitable as a base upon which other layers can build.

See also https://community.jboss.org/docs/DOC-48264 for notes on the impact on the boot process.