File repair mode

[Xyene]

It'd be a good idea to have an option for launching the game in file repair mode directly, to fix broken installs.

I'm thinking a Repair! button next to the current launch button, which would destroy BNSBoost's unpatched directories and start the launcher. The launcher would then repair files, and we can hook CreateProcessW to kill the launcher and redirect back to BNSBoost once the repair is complete.