Fix: Update arrow parsing for new Chessground version

- Update to be compatible with latest lichess (chessground) version
- Bugfix (chrome only): arrows starting from top rank now mask properly

- Arrow sizes in analysis board adjust with move strength like in vanilla Lichess.
- Bugfix: removed exception on pages that don't contain a chessboard.

- Choose colors with a built-in color picker! You can still type colors in as before too.
- Access color preferences from the browser toolbar.
- Support dark mode.
- Adjust the opacity of arrows and highlights.
- Change arrow overlap behavior to match lichess.org.
- Support wide arrows, faint arrows, and gray arrows in the analysis board.