Add roof:shape field to building presets?

[lizzyd710]

I've been getting into 3D mapping, and I see that roof color and material are fields you can add in the building preset, but not roof shape. I would be willing to take this on if this is something people would be okay with!

[danieldegroot2]

This is already part of openstreetmap/iD#1829, which is also part of openstreetmap/iD#2550 (comment) .