add body mod support for prosthetics

Makes the game remember the attributes(body mods) added to prosthetics and will reapply them if you reequip a prosthetic you previously had unequipped and that had body mods. Currently does nothing since there are no body mods tied to the limb system.

@lowercasedonkey This is the last MR that touched how limbs work, I don't think there will be any change to the system for the foreseeable future: You can do what ever you want with body mods, you won't get in conflict with me.

@Pregmodder This needs a version increase to make BC run correctly.