This removes redundant labels from various input nodes like the Value, Integer
and Object node.
Design wise, this is mostly straight forward except for two aspects:
* Some input nodes some have a gizmo icon. In this case I just added the gizmo
icon on the same row.
* The checkbox in the Boolean input node should probably still have a label, so
I kept that.
Implementation wise this adds a new function to socket declarations that allows
us to override the draw behavior of individual sockets per node.
Pull Request: https://projects.blender.org/blender/blender/pulls/139432
87c011f8bb