Blender Git Loki

Merge remote-tracking branch 'origin/gsoc-2021-porting-modifiers-to-nodes-solidify' into gsoc-2021-porting-modifiers-to-nodes-solidify

# Conflicts:
# source/blender/blenkernel/BKE_node.h
# source/blender/blenkernel/BKE_solidifiy.h
# source/blender/blenkernel/CMakeLists.txt
# source/blender/blenkernel/intern/node.cc
# source/blender/blenkernel/intern/solidify_nonmanifold.c
# source/blender/makesrna/intern/rna_nodetree.c
# source/blender/modifiers/intern/MOD_solidify.c
# source/blender/nodes/CMakeLists.txt
# source/blender/nodes/NOD_geometry.h
# source/blender/nodes/NOD_static_types.h