Prevent "untracked files" situation by altering `.smm` marker file handling

[budak7273]

If the mod manager encounters a problem while deleting mod files, it could end up leaving some of them behind but still delete the .smm marker file, making it think the folder is an unmanaged mod, leaving behind files that need to be cleaned up manually.

I think I've seen the untracked files issue before, and the solution is to have the .smm marker file be created before extracting any files, but be empty, then the hash written to it after the extraction is complete, and when uninstalling, it should be the last file deleted (i.e. delete all the contents of the folder first, except for that file, then delete the folder)

https://discord.com/channels/555424930502541343/1193986432574963782/1497328490167402576