eables the reading of STL files with mutiple groups and stores patch indices per triangle

src/GridGenerator/geometries/Triangle/Triangle.cu

src/GridGenerator/geometries/Triangle/Triangle.h

...GridGenerator/geometries/TriangularMesh/TriangularMesh.cu

src/GridGenerator/io/STLReaderWriter/STLReader.cpp

src/GridGenerator/io/STLReaderWriter/STLReader.h

targets/apps/HULC/main.cpp