Remove JuliaFunction and a bunch of C code

[fingolfin]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 93.75000% with 1 line in your changes missing coverage. Please review.

Project coverage is 75.52%. Comparing base (696615b) to head (b3c2d48).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/JuliaInterface/src/JuliaInterface.c	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1047      +/-   ##
==========================================
+ Coverage   74.32%   75.52%   +1.20%     
==========================================
  Files          55       55              
  Lines        4514     4478      -36     
==========================================
+ Hits         3355     3382      +27     
+ Misses       1159     1096      -63     

Files with missing lines	Coverage Δ
pkg/JuliaInterface/gap/JuliaInterface.gd	100.00% <ø> (ø)
pkg/JuliaInterface/gap/JuliaInterface.gi	93.25% <100.00%> (-0.50%)	⬇️
pkg/JuliaInterface/src/JuliaInterface.c	74.24% <75.00%> (+7.36%)	⬆️

... and 2 files with indirect coverage changes