Kfsti 668

This is the initial PR  for applying the KC CGB overlay project to KC 6.0. It should obviously be reviewed closely.
No. And there isn't one currently. I added it as part of the cgb work to validate the customer number. You can see here what this file looked like. https://svn.kuali.org/repos/kc/kc-cgb/trunk/src/main/java/org/kuali/kra/rules/SponsorMaintenanceDocumentRule.java. You can also see it was added to SponsorMaintenanceDocument.xml in the cgb overlay here. https://svn.kuali.org/repos/kc/kc-cgb/trunk/src/main/resources/org/kuali/kra/external/datadictionary/docs/SponsorMaintenanceDocument.xml