Use std::filesystem::path in more places

src/Bytecode.cc

src/Bytecode.hh

src/ComputingTasks.cc

src/ConfigFile.cc

src/ConfigFile.hh

src/DynamicModel.cc

src/DynareMain.cc

src/MacroExpandModFile.cc

src/ModFile.cc

src/ModFile.hh

src/ModelEquationBlock.cc

src/ModelTree.cc

src/ModelTree.hh

src/NumericalInitialization.cc

src/NumericalInitialization.hh

src/StaticModel.cc