Updated some of the CPython feature differences:
- Updated status of some features.
- Added CSS to fix table widths to 100% and word wrap.
- Specified explicit table column ratios to improve layout appearance.
- Added missing references to anchors.
- Better consistency with use of formatting and case.
- fix the list of frozen modules in the board info, separate it from the builtin modules
- frozen modules are listed along with the link to their repository
- get the repository by running the git command in the frozen directory
- frozen modules are listed at the end
- they copy the style of the other modules
- frozen modules in build_board_info don't need the URLs, they are filtered out