Remove default expansion from construct_runtime! (#4937)

This removes the following syntactic sugar from `construct_runtime!`:

- Expansion of `default` to the default set of module parts
- Expansion of `System: system` to the default set of module parts

The macro now requires the user to provide all the module parts of a pallet.

substrate/frame/support/procedural/src/construct_runtime/mod.rs

@@ -217,8 +217,8 @@ fn decl_runtime_metadata<'a>(
 				let filtered_names: Vec<_> = module_declaration
 					.module_parts()
 					.into_iter()
-					.filter(|part| part.name != "Module")
-					.map(|part| part.name.clone())
+					.filter(|part| part.name() != "Module")
+					.map(|part| part.ident())
 					.collect();
 				(module_declaration, filtered_names)
 			})