Geometry Nodes: Add node editor option to edit "Operator" node groups

This functions as a way to avoid having the context affect which node
groups are displayed. This is necessary since there is no concept of an
active operator and most node groups could be used as an operator.

It was considered to make this a more general "No Context" option for
the node editor. That still might happen eventually, but we want to
encourage users to use the modifier context since it allows the
various inspection features to work properly.

@@ -0,0 +12,4 @@
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_output<decl::Vector>("Location").subtype(PROP_DISTANCE);

@@ -0,0 +27,4 @@
+  if (!check_tool_context_and_error(params)) {
+    return;
+  }
+  const float4x4 world_to_object(params.user_data()->operator_data->self_object->world_to_object);

@@ -0,0 +32,4 @@
+  const float3 location_global(cursor.location);
+  const math::Quaternion rotation_global(float4(cursor.rotation_quaternion));
+  params.set_output("Location", math::transform_point(world_to_object, location_global));
+  params.set_output("Rotation", math::to_quaternion(world_to_object) * rotation_global);

@@ -0,0 +32,4 @@
+      case GeometryComponent::Type::Mesh:
+        switch (domain) {
+          case ATTR_DOMAIN_POINT:
+            return *attributes.lookup_or_default<bool>(".select_vert", domain, false);

@@ -73,6 +74,7 @@ class GatherLinkSearchOpParams {
   /** The current node type. */
   const bNodeType &node_type_;
 
+  const SpaceNode &snode_;