Improve overall build process for oxShibboleth

[Djeumen Rolain Bonaventure]

Currently, how dependencies from various gluu projects are specified during the build of oxShibboleth creates duplicate library version conflicts , runtime errors which are difficult to track and forces us to maintain and update a list of libraries to exclude.
This could be improved by including gluu-core-com as a dependency so the right versions are pulled.

It would also be nice if the build script was better integrated with the building of the war. Currently , the war is unpacked , then packed. It may be more streamlined to simply rely on the well written Shibboleth IDP maven build script where shibboleth IDP dependencies are pulled directly from maven. It will make it easy too for us to include our plugins and whatnot.