[enhancement] Button to Lichess Analysis in Study Screen

[lymnyx]

It would be useful if there was a button in the study screen for opening the current training move in Lichess Analysis. Currently one would, when wanting to quickly check a newly-spotted response to the current position in Chessdriller, either have to manually setup the position in the board editor or find it in the respective study.

It could also be integrated as an option that appears for entries of the move list when hovering over them, allowing to quickly analyse any position of the line already played.

The general link structure for the redirect on the button would be https://lichess.org/analysis/{FEN with underscores instead of spaces}?color=[white|black] (example link).

Thanks for the great project!

[sflofty]

This feature was added in #139. This issue can be closed imo

• clicking on "Lichess" button will open lichess with the current line at current position
• we also added a back button, so that you can open the previous position, even after making a correct guess