Add lattice of one-parameter subgroups

[paemurru]

In toric geometry, the character lattice and the lattice of one-parameter subgroups are dual to each other. Confusingly, sometimes the character lattice was used where the lattice of one-parameter subgroups should have been used. This pull request fixes this.

[codecov]

Codecov Report

Attention: Patch coverage is 74.28571% with 9 lines in your changes missing coverage. Please review.

Project coverage is 84.39%. Comparing base (351c1fb) to head (720e746).
Report is 87 commits behind head on master.

Files with missing lines	Patch %	Lines
...etry/ToricVarieties/ToricMorphisms/constructors.jl	73.91%	6 Missing ⚠️
experimental/Schemes/src/ToricBlowups/types.jl	57.14%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4529      +/-   ##
==========================================
- Coverage   84.40%   84.39%   -0.01%     
==========================================
  Files         672      672              
  Lines       89134    89135       +1     
==========================================
- Hits        75230    75228       -2     
- Misses      13904    13907       +3     

Files with missing lines	Coverage Δ
...xperimental/Schemes/src/ToricBlowups/attributes.jl	93.54% <100.00%> (ø)
.../ToricVarieties/NormalToricVarieties/attributes.jl	98.67% <100.00%> (+<0.01%)	⬆️
...ometry/ToricVarieties/ToricMorphisms/attributes.jl	80.21% <100.00%> (ø)
src/deprecations.jl	0.00% <ø> (ø)
experimental/Schemes/src/ToricBlowups/types.jl	72.72% <57.14%> (ø)
...etry/ToricVarieties/ToricMorphisms/constructors.jl	67.85% <73.91%> (ø)

... and 2 files with indirect coverage changes

[simonbrandhorst]

Looks good to me.

[HereAround]

Thank you for working on this @paemurru . Looks good to me!