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: freesasa
  version: 2.1.0
source:
  sha256: dca2a71f5a315aff3ad8ee96130d0e17003265d82241378ffc0dcb0f98bf2203
  url: https://files.pythonhosted.org/packages/a8/af/66991b63b705cd1e1c77fdaec157747275ba5c27b5c9dff7a2e35a43477a/freesasa-2.1.0.tar.gz
test:
  imports:
  - freesasa

package:
  name: freesasa
  version: 2.1.0
source:
  sha256: dca2a71f5a315aff3ad8ee96130d0e17003265d82241378ffc0dcb0f98bf2203
  url: https://files.pythonhosted.org/packages/a8/af/66991b63b705cd1e1c77fdaec157747275ba5c27b5c9dff7a2e35a43477a/freesasa-2.1.0.tar.gz
test:
  imports:
  - freesasa
