Doing simple operations with geometry nodes can be more overwhelming
than it needs to be. That's partly because most of the nodes are fairly
low-level operations. While we can't have "uber nodes" yet, it makes
sense to add some simple nodes for the most common operations.

We already have a couple nodes specifically for changing the "rotation"
attribute on points, so nodes for the "position" and "scale" attributes
make sense as a next step.

I wasn't sure whether I should include the "type" drop-down here, it's
sort of nice to avoid it on these simpler nodes. At the moment the patch doesn't
have them, but they could easily be added. We already have the "Transform"
node for the "constant" version of the translate node, but there is no
existing constant operation for point scales.