This patch makes the point distribute node write to the "rotation"
attribute with the normal of each face at each distributed point.

The conversion from the triangle normal to an Euler rotation is somewhat
arbitrary, since we only have one piece of information. Ideally we would
use some non-arbitrary tangent vector to define each point's local Z axis
rotation. However, the user will probably want to use some setup like in
the following image to randomize each point's rotation anyway.

That's actually an open implementation question for me. It looks like the
tangents exist in the CD_TANGENT data layer. We still need to expose
custom data layers like that to the attribute system though (see T84297).
Because this is unresolved, I consider this patch more of a prototype.

Ref T83362