Add auto stat mods to hit minimum required stats in JS Loadout Optimizer

[robojumper]

Drops support for elemental general mods (because they don't exist (knock on wood)) and adds some code that can moderately efficiently support the already quite complex problem of assigning stat mods to hit stat minimums. This is slower than Rust/wasm but it's fast enough in my testing.

This does not add general support to add stat mods beyond the required minimums because that fundamentally changes the problem statement (feasability -> optimal solution) and I have no idea how to make that work well.