Refactor: Remove BKE_XXX_localize(), in favor of using regular ID copying code.

Besides the NodeTree case (which remains unchanged), the localize code
is only used in one place (to generate previews of shading data-blocks).

This commit introduces a new `LIB_ID_CREATE_LOCAL` option for ID
creation/copying, which essentially implements the behavior of the
removed `BKE_XXX_localize()` functions into regular mainstream ID copy
code. When this option is set:
- new ID is tagged with `LIB_TAG_LOCALIZED`;
- Some ID copying callbacks have specific behaviors, mainly the root
  nodetree of shading IDs gets duplicated with specialized
  `ntreeLocalize()` function.

Note that I would not consider getting rid of `ntreeLocalize` for now,
this function is recursive, which should ideally never happen within ID
management copying code (this introduces all kind of complications).

No behavioral change expected from this commit.

source/blender/editors/render/render_preview.c

@@ -325,7 +325,13 @@ static World *preview_get_localized_world(ShaderPreview *sp, World *world)
   if (sp->worldcopy != NULL) {
     return sp->worldcopy;
   }
-  sp->worldcopy = BKE_world_localize(world);
+
+  ID *id_copy;
+  BKE_id_copy_ex(NULL,
+                 &world->id,
+                 &id_copy,
+                 LIB_ID_CREATE_LOCAL | LIB_ID_COPY_LOCALIZE | LIB_ID_COPY_NO_ANIMDATA);
+  sp->worldcopy = (World *)id_copy;
   BLI_addtail(&sp->pr_main->worlds, sp->worldcopy);
   return sp->worldcopy;
 }
@@ -339,13 +345,16 @@ static ID *duplicate_ids(ID *id)
 
   switch (GS(id->name)) {
     case ID_MA:
-      return (ID *)BKE_material_localize((Material *)id);
     case ID_TE:
-      return (ID *)BKE_texture_localize((Tex *)id);
     case ID_LA:
-      return (ID *)BKE_light_localize((Light *)id);
-    case ID_WO:
-      return (ID *)BKE_world_localize((World *)id);
+    case ID_WO: {
+      ID *id_copy;
+      BKE_id_copy_ex(NULL,
+                     id,
+                     &id_copy,
+                     LIB_ID_CREATE_LOCAL | LIB_ID_COPY_LOCALIZE | LIB_ID_COPY_NO_ANIMDATA);
+      return id_copy;
+    }
     case ID_IM:
     case ID_BR:
     case ID_SCR: