Organize replays into folders

[PKPenguin321]

A really small change that makes it so replays are now saved under Replays/levelId/difficultyMult/, rather than just /Replays. Example: A replay for Incongruence at 0.5x would be saved under Replays\ohvrvanilla_vittorio_romeo_hypercube_1_incongruence\0.5x\replayName.ohr.z

Tested and confirmed functional, and a quick code read indicates that it should not affect uploading to leaderboards (I seem to be unable to actually test this locally however, I assume logging in to the server is disabled via the github build)