Fix T97724: Node Wrangler: better align nodes on texture setup

* The added nodes are now top aligned with the nodes they belong to. This looks
  nicer and works independent of screen DPI.
* There is a vertical offset based on the socket the added nodes are connected
  to. This prevents nodes from overlapping too much, when executing the texture
  setup several times in a row.
* Ignore disabled sockets, which would create nodes seemingly connected to
  nothing.

Differential Revision: https://developer.blender.org/D15031