Provide maven properties providing the short name of EAP XP and it's short version

Provide two maven properties in the jboss-eap7 parent pom to provide information about the related JBoss EAP expansion pack:

expansion.pack.release.name. -> value "JBoss EAP XP"
expansion.pack.release.version -> value "1.0.0.GA" (initially)

The value of the former is meant to be the formal "short name" of the expansion pack.
The value of the latter is meant to reflect the short form version number of the expansion pack release that will be derived from the code in the jboss-eap7 branch. It is analogous to 'full.dist.product.release.version' which would have a value of "7.3.0.GA", then "7.3.1.GA" for 7.3 CP1, then "7.3.2.GA" for CP 2 etc. Similarly the expansion pack patches will have the short identifier "1.0.0.GA", "1.0.1.GA" etc.

These are short identifiers in that they are not full formal maven version strings like "7.3.1.GA-redhat-00001".

These properties (at least the version one) are intended for use in driving productization tasks, and they will also be used in my intended solution for an XP vs base dependency alignment check the JIRA for which I'll file shortly.