Basic c++ documentation addition

[AlexManochis]

This PR contributes C++ documentation tools and content

[codecov]

Codecov Report

Merging #253 (376d7f8) into develop (fbc4206) will increase coverage by 0.08%.
The diff coverage is 52.63%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #253      +/-   ##
===========================================
+ Coverage    53.88%   53.96%   +0.08%     
===========================================
  Files          105      105              
  Lines         6169     6167       -2     
  Branches      2872     2874       +2     
===========================================
+ Hits          3324     3328       +4     
+ Misses         972      965       -7     
- Partials      1873     1874       +1     

Impacted Files	Coverage Δ
include/cartesian_geom/point.h	62.00% <ø> (ø)
include/convex_bodies/ball.h	65.62% <0.00%> (ø)
include/convex_bodies/ballintersectconvex.h	88.88% <ø> (ø)
include/convex_bodies/convex_body.h	0.00% <ø> (ø)
...onvex_bodies/correlation_matrices/corre_matrix.hpp	69.04% <ø> (ø)
...correlation_matrices/correlation_spectrahedron.hpp	66.23% <ø> (ø)
...relation_matrices/correlation_spectrahedron_MT.hpp	50.00% <ø> (ø)
include/convex_bodies/hpolytope.h	75.82% <ø> (ø)
include/convex_bodies/orderpolytope.h	65.13% <ø> (ø)
include/convex_bodies/spectrahedra/spectrahedron.h	8.33% <ø> (ø)
... and 29 more

[vissarion]

Thanks!

[elias-tsigaridas]

It looks ok to me.

[TolisChal]

Thank you for this really useful PR! Good work!