`sage --package create --pypi`: Fill `distros/`

[mkoeppe]

Except for exceptions, the package names of Python packages in distributions follow simple naming schemes.

When creating a new PyPI package using sage --package create --pypi, we should be able to create the files in distros/ as well.

[mkoeppe]

• conda.txt could be obtained using grayskull once sufficiently stable, as proposed in #37447. Doubts: It's dead, Jim. https://github.com/conda/grayskull/graphs/contributors, https://github.com/conda/grayskull/issues

• Use of a skeleton generator would obviously be more appropriate as part of sage --package create (= at package maintenance time) than at bootstrapping time as suggested in #37447

• A proof-of-concept tool py-show by @rgommers from the PEP 725 effort has some package mappings for arch, fedora, ubuntu, conda (and also some simple version of our sage-print-system-package-command)

Other relevant tools:

• https://github.com/package-url/packageurl-python

[rgommers]

I need to give PEP 725 another push soon. In case you find gaps in the metadata, I'd be happy to learn/address. Also, grayskull now has initial PEP 725 support which may be relevant:

• https://github.com/conda/grayskull/pull/518
• https://github.com/conda/grayskull/pull/528