Remove libpython output

`libpython` is becoming a real output for the python recipe itself (https://github.com/conda-forge/python-feedstock/pull/894). We need to remove the output here, change all (non-archived) consuming recipes, and then likely repodata-patch existing builds to point to `distutils-activate-mingw` instead, and mark the old builds as broken.

This [search](https://github.com/search?q=org%3Aconda-forge+%2F-+libpython%5B%5E%5C-%5D%2F+path%3Arecipe%2F*.yaml&type=code) finds 16 non-archived feedstocks that use this:

* [x] https://github.com/conda-forge/anuga-feedstock/pull/24
* [x] https://github.com/conda-forge/awex-feedstock/pull/17
* [x] https://github.com/conda-forge/capytaine-feedstock/pull/53
* [ ] https://github.com/conda-forge/eatpy-feedstock/pull/13
* [x] https://github.com/conda-forge/finesse-feedstock/pull/77
* [ ] https://github.com/conda-forge/framel-feedstock/pull/51
* [ ] https://github.com/conda-forge/gala-feedstock/pull/42
* [ ] https://github.com/conda-forge/gdcm-feedstock/pull/69
* [ ] https://github.com/conda-forge/nds2-client-swig-feedstock/pull/45
* [x] https://github.com/conda-forge/pygetm-feedstock/pull/39
* [x] https://github.com/conda-forge/pygotm-feedstock/pull/20
* [x] https://github.com/conda-forge/pyhams-feedstock/pull/35
* [x] https://github.com/conda-forge/pyreadr-feedstock/pull/61
* [x] https://github.com/conda-forge/python-quickjs-feedstock/pull/13
* [ ] https://github.com/conda-forge/rvlib-feedstock/pull/31
* [x] https://github.com/conda-forge/wisdem-feedstock/pull/109