Add PDFastSimPAR as a one of the tools for the OpticalPropagation EDProducer module

[stognini]

This PR moves the code from PDFastSimPAR_module to a new OpticalPropPDFastSimPAR tool, derived from IOpticalPropagation. This tool is used by the new OpticalPropagation_module, which will substitute PDFastSimPAR_module and will be the main mechanism for transporting optical photons through Celeritas or Opticks, which will be added as concrete implementations of the IOpticalPropagation tool interface.

[stognini]

There are multiple loose ends still in this draft PR still.

TODOS:

• The fcl files all require an overhaul and testing.
• The fast sim tool requires the construction of 2 RNG engines used by two other tools. These RNGs are initialized in the OpticalPropagation module constructor via OpticalPropPDFastSimPAR::InitializeTools, but I am not sure this is the best way to do it.
• The make_tool invocation in the OpticalPropagation module constructor needs attention.
• The code does not build yet:

[ 20%] Building CXX object larsim/larsim/PhotonPropagation/CMakeFiles/larsim_PhotonPropagation_OpticalPropagation_module.dir/OpticalPropagation_module.cc.o
[ 20%] Linking CXX shared module ../../slf7.x86_64.e26.prof/lib/liblarsim_PhotonPropagation_OpticalPropagation_module.so
/usr/bin/ld: Dwarf Error: found dwarf version '5', this reader only handles version 2, 3 and 4 information.
CMakeFiles/larsim_PhotonPropagation_OpticalPropagation_module.dir/OpticalPropagation_module.cc.o: In function `phot::OpticalPropagation::OpticalPropagation(art::ProducerTable<phot::OpticalPropPDFastSimPAR::Config, art::detail::ModuleConfig, void> const&)':
OpticalPropagation_module.cc:(.text+0x19d7): undefined reference to `typeinfo for phot::OpticalPropPDFastSimPAR'
OpticalPropagation_module.cc:(.text+0x1bf6): undefined reference to `phot::OpticalPropPDFastSimPAR::InitializeTools(CLHEP::HepRandomEngine&, CLHEP::HepRandomEngine&)'