Added fluid Gold Iron Pipe (probably needs a name change)

As discussed on #1210.

This pipe will use the largest flow rate of the pipes surrounding it.
Doesn't have any textures yet because I'm not good with that.
Probably needs a new recipe (current is 1 golden pipe and 1 iron pipe), and maybe a new name?

I think it should be made of a new material, maybe ender pearls or something like that.
What do you guys think?