Task #9800: support for remote clusters in Hertfordshire and Juelich. changes in command construction and special handling of node setup.

Task #9127: revert part of r35157 that removes AOFlagger_SOURCE_DIR from LofarPackageList.cmake to restore daily LofIm build on lhn002. This is not the real solution, the daily build must be fixed to take AOFlagger externally. This will break again on the next run+commit of gen_LofarPackageList_cmake.sh.

Task #9127: add new Dragnet LOFAR and IERS install and activate scripts to SubSystems/Dragnet/scripts. Still some hard-coded version numbers.

Task #9127: add SubSystems pkg: Dragnet. Update LofarPacakgeList.cmake (also removes already disabled AOFlagger entry from pkg list)

Task #9127: update compiler default cmake files: uniformize OPTARCH, add -stdlib=libc++ to CLANG (acked-by Tammo Jan Dijkema)