extend docs

[DerThorsten]

There is now docs at https://emscripten-forge.org with very little content, lets add:

• [x] use packages with lite / xeus-python
• [ ] debug local builds: This should describe how to use the rattler-build way of debugging.
• [x] credit section
• [ ] todo section
• [x] blog / news section
• [x] global pinning / conda-build-config
• [ ] maintainers section:
  • [ ] overview of ci itself
  • [ ] uploading packages via ci
  • [ ] building/extending the documentation
  • [ ] bots
• [ ] hints how to add packages:
  • [ ] header only c++
  • [ ] static library c++
  • [ ] shared library c++
  • [ ] python with:
    • [ ] pybind11
    • [ ] libffi
    • [x] meson
    • [x] rust (#935 )

[anutosh491]

As we have quite some "r-XX" packages now, we should document how one can add more.