chessvision-ai-bot introduces more hints

I added more hints to the bot. Now, besides piece and move hints it provides:

1. Exact engine evaluation, e.g. “White has mate in 2”, “Black is better -3.25”, “The game is equal +0.1”.

2. Full best continuation line by the engine.

All hints are marked as spoilers and they come from Stockfish 10 analysis with depth around 21.

And you can reveal the spoilers by clicking on them

I have to admit that adding new futures for the bot is so much fun.