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: decorator
  version: 5.0.6
source:
  sha256: f2e71efb39412bfd23d878e896a51b07744f2e2250b2e87d158e76828c5ae202
  url: https://files.pythonhosted.org/packages/6a/aa/c194bd2fb168c1ebd8ffbfc12d972d09a9df0e4d485013e5ba2c8e4f1f05/decorator-5.0.6.tar.gz
test:
  imports:
  - decorator

package:
  name: decorator
  version: 5.0.6
source:
  sha256: f2e71efb39412bfd23d878e896a51b07744f2e2250b2e87d158e76828c5ae202
  url: https://files.pythonhosted.org/packages/6a/aa/c194bd2fb168c1ebd8ffbfc12d972d09a9df0e4d485013e5ba2c8e4f1f05/decorator-5.0.6.tar.gz
test:
  imports:
  - decorator
