Merge branch 'add_genfit' into 'master'

Add Genfit v2.0 for contingency

See merge request !70

spack.yaml

@@ -25,6 +25,7 @@ spack:
     - geant4@10.7.1 cxxstd=17 +opengl +vecgeom +x11 +qt ^qt +opengl
     - dd4hep@1.16.1 +geant4 +assimp +hepmc3 +ipo
     - acts@8.02.0p1 +dd4hep +digitization +identification +json +tgeo +ipo
+    - genfit@2.00.00
     - gaudi@34.0
     - dawn@3_91a
     - dawncut@1_54a