docs(v8) Integrate typedoc in documentation

[gpbl]

Website should use the docs from source, and they should be easily linkable.

Notes

• typedoc package helps with its API, but its documentation is lacking
• tsdoc package does only validate tsdoc comments
• probably we should invent a React DayPicker script generating the documentation components
  • markdown should be parsed manually
  • internal links
  • typings
• it would be nice to have the code preview when encountering jsx preview comment blocks