Support overweight messages in XCMP queue (#799)

* Support overweight messages in XCMP queue

* Add storage migration logic to XCMP queue pallet

* Check whether required weight is larger than max individual weight first

* cargo fmt

* Add some unit tests

* Remove review question comment

parachain-template/runtime/src/lib.rs

@@ -521,6 +521,7 @@ impl cumulus_pallet_xcmp_queue::Config for Runtime {
 	type XcmExecutor = XcmExecutor<XcmConfig>;
 	type ChannelInfo = ParachainSystem;
 	type VersionWrapper = ();
+	type ExecuteOverweightOrigin = EnsureRoot<AccountId>;
 }
 
 impl cumulus_pallet_dmp_queue::Config for Runtime {