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

import { loadPyodide, version } from "./pyodide";
export { loadPyodide, version };
(globalThis as any).loadPyodide = loadPyodide;

import { loadPyodide, version } from "./pyodide";
export { loadPyodide, version };
(globalThis as any).loadPyodide = loadPyodide;
