set up conda-forge build

[cchwala]

We also need a conda-forge package, e.g. to add poligrain as dependency of pycomlink which (currently) has not up-to-date pypi package.

Some links with info for building conda-forge packages

• https://conda-forge.org/docs/maintainer/adding_pkgs/
• https://github.com/conda-forge/staged-recipes/blob/main/recipes/example/meta.yaml
• https://github.com/conda-forge/staged-recipes

[cchwala]

This is in progress in https://github.com/conda-forge/staged-recipes/pull/26753

[cchwala]

Done