Social layers

This reverts commit 49a6aff9.

Since human groups are now stored in their own core segment (as
discussed with Fabian) for clearer distinction between humans and human
groups and a cleaner structure.

as a human group segment does not exist and the writer writes it in the
human segment

still missing a way to write the groups like the human writer plugin

This includes:
- using the autoformatter
- consts everywhere
- no more raw pointers