Add support for generating 2D discrete fields

[Gornhoth]

The 2D generation works almost exactly like the 3D one. The signatures were matched as closely as possible and programs are included similar to the 3D solution (GenerateSDF2D, DiscreteFieldToBitmap2D).
Note that for the examples Clipper2 library is used to convert a triangle mesh to a polygon before discretization. However, this dependency is optional and the solution (without the two programs) works without it as well, if the user defines their own polygon structure consistent of vertices and edges to discretize.
If anything in my code is not to up to the standards of the maintainers of Discregrid, please tell me how I can fix things so this pull request can be merged.

[JoseAntFer]

Hello,

thank you for your contribution, however, at the moment I have no time to revise the changes. I will leave it open for now.

[Gornhoth]

Hello!
Thanks for the information, please take your time to review the changes, there is no need to hurry if there is little time at the moment. For my personal interest, may I ask in what time frame it is likely my pull request can be reviewed?

[JoseAntFer]

Sadly, I am not able to give you a time frame as we have a couple of packed months coming. Additionally, we have to discuss internally if we actually want to add support for 2D fields in the main repo of Discregrid as we do not work with 2D and it just becomes more code to maintain for us.

[Gornhoth]

Understandable, thanks for the information and good luck with your upcoming projects!