add easyconfig files for ParaStation MPI

Added easyconfig files (configure/make) for ParaStation MPI with download from github (with alternative download paths via the Open ParaStation project on sourceforge / commented out by default).
ParaStation is a robust and efficient cluster middleware, consisting of a high-performance communication layer (ParaStation MPI) which is the MPI library of choice on the JuRoPA systems of the Jülich Supercomputing Centre (JSC). ParaStation MPI is developed and maintained by ParTec Cluster Competence Center GmbH.