Document scripts for changing EAP database

A script was created to assist reconfiguration of EAP to connect to a production database instead of the default, temporary connection to HSQL. Since this is a new feature which may commonly be used, it needs to be documented.

A similar script was created for SOA-P and its documentation can be found here: https://access.redhat.com/knowledge/docs/en-US/JBoss_Enterprise_SOA_Platform/5/html-single/Installation_and_Configuration_Guide/index.html#Database_Configuration_Tool

Draft documentation created by the developer can be found here: http://anonsvn.jboss.org/repos/jbossas/branches/JBPAPP_5_1/ds-builder/src/etc/README.txt is a modified version of this. This should be OK for the EAP docs.