Add package_type field to repodata.json. ### Description

This PR adds `package_type` field to repodata.json and use it to create a list of unvendored standard libraries. After this we don't need to manage a hard-coded list of unvendored stdlib lists in pyodide-py.

### Checklists

- [x] Add / update tests

package:
  name: pandas
  version: 1.5.2
  tag:
    - min-scipy-stack
  top-level:
    - pandas
source:
  url: https://files.pythonhosted.org/packages/4d/07/c4d69e1acb7723ca49d24fc60a89aa07a914dfb8e7a07fdbb9d8646630cd/pandas-1.5.2.tar.gz
  sha256: 220b98d15cee0b2cd839a6358bd1f273d0356bf964c1a1aeb32d47db0215488b
build:
  cflags:
    -Werror=implicit-function-declaration -Werror=mismatched-parameter-types
    -Werror=mismatched-return-types -Oz
  ldflags: --Wl,--fatal-warnings -Oz
requirements:
  host:
    - numpy
  run:
    - distutils
    - numpy
    - python-dateutil
    - pytz
    - setuptools
about:
  home: https://pandas.pydata.org
  PyPI: https://pypi.org/project/pandas
  summary: Powerful data structures for data analysis, time series, and statistics
  license: BSD-3-Clause

package:
  name: pandas
  version: 1.5.2
  tag:
    - min-scipy-stack
  top-level:
    - pandas
source:
  url: https://files.pythonhosted.org/packages/4d/07/c4d69e1acb7723ca49d24fc60a89aa07a914dfb8e7a07fdbb9d8646630cd/pandas-1.5.2.tar.gz
  sha256: 220b98d15cee0b2cd839a6358bd1f273d0356bf964c1a1aeb32d47db0215488b
build:
  cflags:
    -Werror=implicit-function-declaration -Werror=mismatched-parameter-types
    -Werror=mismatched-return-types -Oz
  ldflags: --Wl,--fatal-warnings -Oz
requirements:
  host:
    - numpy
  run:
    - distutils
    - numpy
    - python-dateutil
    - pytz
    - setuptools
about:
  home: https://pandas.pydata.org
  PyPI: https://pypi.org/project/pandas
  summary: Powerful data structures for data analysis, time series, and statistics
  license: BSD-3-Clause
