Long term we should move everything over to `pyproject = true`, but in
the mean time we can work towards deprecating the implicit `format` paremeter.
cc https://github.com/NixOS/nixpkgs/issues/253154
cc @mweinelt @figsoda
The `buildPython*` function computes name from `pname` and `version`.
This change removes `name` attribute from all expressions in
`pkgs/development/python-modules`.
While at it, some other minor changes were made as well, such as
replacing `fetchurl` calls with `fetchPypi`.
