Allow never-type goals in lockout

[RasmusAntons]

After transitioning from a different mod for lockout, we wanted to be able to reimplement some of the goals in a datapack, especially negative goals that prohibit you from doing something in the game.

This code probably isn't great, but it adds a possible implementation for that. The logic is that initially every team is eligible to get the goal, shown by a split background colour. Once all but one team have lost the condition, that last team gets the point.

This probably shouldn't be active by default because it requires some consideration for goals. The goals need to either be easy to get accidentally, like "never take fall damage" or be possible for other teams to enforce, like "never die" (especially when playing with a player tracker). I added the start parameter --allow-never-goals-in-lockout for that.

[RasmusAntons]

Oh, I forgot. There still needs to be a check for if all the remaining goals are never goals, and triggering an immediate end if so.

Would it be an option to make goals that will be skipped if nothing else is left another special tag? Some never goals would be okay at the end of the game, for example a game tied on 12-12 with "never die" left (if you're playing with a player tracker and are able to find and attack the other team).

[RasmusAntons]

During playtesting today we also found out that a negative goal being awarded doesn't trigger the check for game winning so I'll work on that too.

[RasmusAntons]

I think this works, but I'm not sure if the stalemate tag could cause confusion, being only relevant for lockout gamemode.

[Gaming32]

I'd prefer if the stalemate tag was the default case, since most never goals will lead to a stalemate if lost.