Introduce a method of Alternative Scoring

[Morxemplum]

By default, Open Hexagon uses a timer for how long the player survives to score an attempt. This will always be the default method of scoring in Open Hexagon. However, from seeing some of the creativity in some of the player packs, some levels don't suit very well when scored by the amount of time they've survived in an attempt.

What I plan on doing is being able to override the default scoring value and be able to bind it to a custom Lua variable that the user defines, and the variable that has been bound will replace the timer as a way of scoring. This will also be bound to personal bests and will also be prevalent with the level's leaderboard.

This can actually make a lot more level ideas be possible by introducing a way to customize how levels can be scored. I think this is a "Should Have"