[FTheoryTools] Implement G4-fluxes

[HereAround]

A first implementation of G4-fluxes.

[codecov]

Codecov Report

Attention: Patch coverage is 75.92593% with 26 lines in your changes missing coverage. Please review.

Project coverage is 84.32%. Comparing base (77a500e) to head (e6171e0).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3965      +/-   ##
==========================================
- Coverage   84.33%   84.32%   -0.02%     
==========================================
  Files         593      596       +3     
  Lines       81750    81853     +103     
==========================================
+ Hits        68945    69022      +77     
- Misses      12805    12831      +26     

Files	Coverage Δ
...perimental/FTheoryTools/src/G4Fluxes/attributes.jl	100.00% <100.00%> (ø)
experimental/FTheoryTools/src/types.jl	95.12% <100.00%> (+0.12%)	⬆️
...ometry/ToricVarieties/CohomologyClasses/methods.jl	61.53% <100.00%> (+1.53%)	⬆️
...cVarieties/CohomologyClasses/special_attributes.jl	100.00% <100.00%> (ø)
...perimental/FTheoryTools/src/G4Fluxes/properties.jl	90.47% <90.47%> (ø)
...heoryTools/src/AbstractFTheoryModels/attributes.jl	96.45% <85.71%> (-2.13%)	⬇️
...rimental/FTheoryTools/src/G4Fluxes/constructors.jl	40.00% <40.00%> (ø)

... and 1 file with indirect coverage changes

[apturner]

This same block of code appears in the calculations of c1, c2, the equality check for fluxes, and here. Perhaps we should make this its own function and store the result in an attribute.

[HereAround]

Yeah. Or we add an attribute to Weierstrass and global Tate models that allows us to call hypersurface_equation in those cases to extract the value of weierstrass_polynomial, respectively tate_polynomial. I will try to remember this for a future PR.