feature: Option when creating game to restrict to theoretically winnable decks

[timotree3]

A few thoughts:

• At first glance knowing that the deck is winnable might seem like an advantage, but for those who play for winrate, they are already logically assuming that the deck is winnable with every decision that they make.
• I'm not sure what the formula is for whether a deck is winnable. Certainly having a card like black 4 at the bottom makes it unwinnable, but I'm sure there's other ways to make it unwinnable. Maybe for an initial implementation we just prevent critical non-5 cards from being at the bottom.

[Zamiell]

we've decided against this in the past overall, the code complexity cost is not worth the convenience of the feature https://www.productplan.com/feature-bloat/