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.
ARG VERSION

FROM pyodide/pyodide-env:${VERSION}

USER root

ENV EMSDK_NUM_CORES=4 EMCC_CORES=4 PYODIDE_JOBS=4

COPY . pyodide

# the rm at the end deletes the build results such that the resulting image can still be used for building pyodide
# from source (including partial and customized builds). Due to the previous run of make, builds
# executed with this image will be much faster than the ones executed with pyodide-env
RUN cd pyodide && make && rm -r ./build

ARG VERSION

FROM pyodide/pyodide-env:${VERSION}

USER root

ENV EMSDK_NUM_CORES=4 EMCC_CORES=4 PYODIDE_JOBS=4

COPY . pyodide

# the rm at the end deletes the build results such that the resulting image can still be used for building pyodide
# from source (including partial and customized builds). Due to the previous run of make, builds
# executed with this image will be much faster than the ones executed with pyodide-env
RUN cd pyodide && make && rm -r ./build
