Adds a multiplier to cursor speed in menus.

i had installed payday 2 again after a slight hiatus and immediately noticed how obnoxiously fast the pointer is by default,
i couldn't find a mod to fix it, and saw a comment lamenting the same issue, so here we are

as of writing this, before the last 3 hours i had never written a line of lua, but it turned out good enough.
happy heisting

15-01-2025 update: fixed drawing in preplanning