Check out/in assets when teleporting to maintain total issuance (#3007)

* Check out/in assets when teleporting to maintain total issuance

* Fixes

* Fixes

* Fixes

* Fixes

* Update xcm/xcm-executor/src/traits/transact_asset.rs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

* Docs

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

polkadot/runtime/westend/src/lib.rs

@@ -839,6 +839,7 @@ parameter_types! {
 	pub const WndLocation: MultiLocation = MultiLocation::Null;
 	pub const Ancestry: MultiLocation = MultiLocation::Null;
 	pub WestendNetwork: NetworkId = NetworkId::Named(b"Westend".to_vec());
+	pub CheckAccount: AccountId = XcmPallet::check_account();
 }
 
 pub type LocationConverter = (
@@ -856,6 +857,8 @@ pub type LocalAssetTransactor =
 		LocationConverter,
 		// Our chain's account ID type (we can't get away without mentioning it explicitly):
 		AccountId,
+		// It's a native asset so we keep track of the teleports to maintain total issuance.
+		CheckAccount,
 	>;
 
 type LocalOriginConverter = (