alias ginger_hair → orange_hair

BUR #736 is pending approval.

create alias ginger_hair -> orange_hair

While ginger hair is a more natural fit for photorealistic images, in context of a booru and anime-style images, it is simpler to just call it orange. All of the posts with the ginger_hair tag, are just orange.

I haven't looked at the tag posts but I'd say deprecating is probably better. Ginger can be red, orange, or blonde hair.