Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
Unvendor distutils. Packages the distutils stdlib module as a standalone package,
```
377K distutils.data
221K distutils.data.br
19K distutils.js
```
to reduce the minimal pyodide size.

Part of #1542 

This also,
 - adds documentation on what's supported or not in the stdlib
 - makes a few changes to `pyodide_build/buildall.py` to be able to add such stdlib packages as a dependency in other packages (which didn't work before). For instance, until there is a release with https://github.com/pypa/packaging/pull/396 micropip has a dependency on distutils.
package:
  name: more-itertools
  version: 8.7.0
source:
  sha256: c5d6da9ca3ff65220c3bfd2a8db06d698f05d4d2b9be57e1deb2be5a45019713
  url: https://files.pythonhosted.org/packages/fd/2d/90ea8e03076d46166b14c24c87b07ef8cf3d4e0df9a59aefbbd4db3bef7b/more-itertools-8.7.0.tar.gz
test:
  imports:
  - more_itertools

package:
  name: more-itertools
  version: 8.7.0
source:
  sha256: c5d6da9ca3ff65220c3bfd2a8db06d698f05d4d2b9be57e1deb2be5a45019713
  url: https://files.pythonhosted.org/packages/fd/2d/90ea8e03076d46166b14c24c87b07ef8cf3d4e0df9a59aefbbd4db3bef7b/more-itertools-8.7.0.tar.gz
test:
  imports:
  - more_itertools
