[Suggestion] Add invisible (top, mid and low) headgear costumes
Description
What the title says.
Rationale
Benefit is for pure aesthetic reasons, to choose hiding equip we wouldn't like to show and not having to wear any other, and have the class sprite as is or just to enhance the look of a headgear we like alone, without other hats getting in the way.
Additional Information
It could do as another nice zeny sink. Gemmed Sallet (for Merchant, Swordman, Thief classes) already works (as a bug and not a feature, I suppose) like an invisible upper headgear for some players.