Give players the option to play against either FSF or YaneuraOu

[Eventlesstew]

https://lishogi.org/forum/general-shogi-discussion/i-am-struggling-against-the-level-2-bot-and-its-killing-my-enjoyment-of-the-game#8

I think there should be a separate dropdown option that allows players to play AI Shogi games against either Fairy Stockfish or YaneuraOu (Labelled as Expert) since YaneuraOu is a bit too much of a challenge to be a Level 2 bot. (It's more like level 4-5.)

[WandererXII]

Hmm, this would be hard to combine with the presets in the lobby... I don't think I can make yane easier to defear, so maybe using fairy for lvls 1, 2 and 3... Currently the jump from lvl 1 to lvl 2 is certainly too big...
There is also an option to play handicaps if the ai is too difficult.

[Eventlesstew]

For Presets, you could probs use the same skill system. The user starts with Fairy Stockfish, then as the player's skill climbs, the "Hard" preset uses YaneuraOu, (Marked as Expert Lv# or smth) then "Medium" would eventually get YaneuaOu. The "Easy" preset always has FSF.

But reserving FSF for levels 1-3 is better for simplification purposes.