Ports inacusiate from /vg/station, a chemical that instantly heals hearing damage and deafness

https://github.com/d3athrow/vgstation13/pull/712

Pretty much a straight port except that I lowered the resulting amount from 3 to 2 to match with imidazoline. It being instant can be changed if desired but considering how being deaf is mostly just really obnoxious I'm leaving it as is for now.

Note that the only way you can heal hearing damage above 25 currently is by wearing earmuffs.