PyAPI: use bpy_rna_types_capi.c to set type methods

Remove use of '_bpy' as an intermediate module to store functions
which were then assigned in bpy_types.py.

source/blender/python/intern/bpy.c

@@ -380,10 +380,7 @@ void BPy_init_modules(void)
   PyModule_AddObject(mod, "types", BPY_rna_types());
 
   /* needs to be first so bpy_types can run */
-  BPY_library_load_module(mod);
-  BPY_library_write_module(mod);
-
-  BPY_rna_id_collection_module(mod);
+  BPY_library_load_type_ready();
 
   BPY_rna_gizmo_module(mod);