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.

@@ -33,0 +49,4 @@
+AssetItemTree build_filtered_all_catalog_tree(
+    const bContext &C,
+    const AssetFilterSettings &filter_settings,
+    FunctionRef<bool(const AssetMetaData &)> meta_data_filter);

@@ -44,0 +51,4 @@
+
+namespace blender::ed::asset {
+
+AssetItemTree build_filtered_all_catalog_tree(

@@ -130,0 +133,4 @@
+
+namespace blender::ed::asset {
+
+asset_system::AssetLibrary *get_all_library_once_available()

@@ -44,0 +89,4 @@
+    return true;
+  });
+
+  /* Build an own tree without any of the catalogs that don't have proper node group assets. */

@@ -0,0 +253,4 @@
+        *node_tree,
+        op->properties,
+        compute_context,
+        geometry_orig,

@@ -0,0 +298,4 @@
+  return BLI_strdup(description);
+}
+
+void GEOMETRY_OT_execute_node_group(wmOperatorType *ot)

@@ -0,0 +322,4 @@
+  return CTX_wm_view3d(C);
+}
+
+// TODO: SHOULD BE SHARED

@@ -0,0 +414,4 @@
+      menus.add_new("Select");
+      menus.add_new("Curves");
+      break;
+    case OB_MESH:

@@ -7436,2 +7436,4 @@
   };
 
+  static const EnumPropertyItem geometry_nodes_type_items[] = {
+      {SNODE_GEOMETRY_MODIFIER, "MODIFIER", 0, "Modifier", ""},

@@ -83,2 +90,4 @@
    */
   GeoNodesModifierData *modifier_data = nullptr;
+  /**
+   *