Upgrade everything to XsltCompiledTransform

It is not completely clear where are we using OldXsltEngine. It seems to be used by rule processing in Architect, making it hard to debug some problems because of a difference in behavior between the Architect and the Server. It should not be used for anything these days.

This class should be removed from the source code, including XsltEngineType.XslTransform enum.

It is possible that metamodel has to be upgraded as transformations/rules might still be using XslTransform parameter.

Please review also why mvp.xml is still in the final build and remove the reason for it.