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: cytoolz
  version: 0.11.0
source:
  sha256: c64f3590c3eb40e1548f0d3c6b2ccde70493d0b8dc6cc7f9f3fec0bb3dcd4222
  url: https://files.pythonhosted.org/packages/58/67/1c60da8ba831bfefedb64c78b9f6820bdf58972797c95644ee3191daf27a/cytoolz-0.11.0.tar.gz
requirements:
  run:
  - nose
  - toolz
test:
  imports:
  - cytoolz

package:
  name: cytoolz
  version: 0.11.0
source:
  sha256: c64f3590c3eb40e1548f0d3c6b2ccde70493d0b8dc6cc7f9f3fec0bb3dcd4222
  url: https://files.pythonhosted.org/packages/58/67/1c60da8ba831bfefedb64c78b9f6820bdf58972797c95644ee3191daf27a/cytoolz-0.11.0.tar.gz
requirements:
  run:
  - nose
  - toolz
test:
  imports:
  - cytoolz
