Settings Menu for Sound

Added a settings menu for sound mostly due to realizing that the sound of the game was a lot quieter than expected sans earbuds whoops. I hope being able to set the audio levels should fix this issue. At the very least it lets audio be customizable which has always been something I've personally appreciated. While I'm writing this, I realize there's not really an option to mute the audio of this game in game... oops that's an oversight. Maybe I should fix that at some point...

Edit: adjustment made, and mute buttons added