Add a layer between universal + specific native packages

Creates a layer between universal packaging and specific native packages in an attempt to reduce the necessary overhead of defining native packages.

* Create a layer above raw XML for configuring windows packages (nascent right now)
* Add symlink support to debian/rpm packaging
* Create mappings from universal layout -> linuxPackageMappings
* Create mappings from universal layout -> windows feature set
* Update documentation to be easier to follow and more helpful (we hope).