XCM revamp & Ping pallet (#391)

* Add spambot

* Fixes

* Add some extra functions to spambot, bump version

* Lock..

* Aggregate HRMP (XCMP/HMP) messages. Payloads for spambot.

* Fix tests, bump Polkadot.

* Fix HMP tests

* Rename Hrmp -> Xcmp for handler/sender

* Use master branch

* Test Xcm message passing & rename away from HMP

* Docs

* Introduce fee payment mechanics into XCM.

* Rename spambot -> ping

* Lock

* XCMP message dispatch system reimagining

- Moved most of the logic into xcm-handler pallet
- Altered the outgoing XCMP API from push to pull
- Changed underlying outgoing queue data structures to avoid multi-page read/writes
- Introduced queuing for incoming messages
- Introduced signal messages as a flow-control sub-stream
- Introduced flow-control with basic threshold back-pressure
- Introduced overall weight limitation on messages executed
- Additonal alterations to XCM APIs for the new system

* Should process any remaining XCM messages when we're not doing anything else.

* Update API usage and preparation for the big build.

* Some build fixes

* Build fixes

* xcm-handler builds

* Fix warnings

* Docs

* Parachains system builds

* Parachain runtime building

* Fix build

* Introduce transfer_asset specialisation.

* Fixes

* Two-stage upgrade for parachains.

* Fixes

* Fixes

* Updates for message sending.

* Repotting/renaming. Add primitives/utility.

* Remove real-overseer and bump refs

* Configure & document Rococo XCM runtime.

* Add shell runtime, some companion changes for #8589

* Bumps & fixes

* Fix test

* Build fix

* Update pallets/xcmp-queue/src/lib.rs

Co-authored-by: Amar Singh <asinghchrony@protonmail.com>

* Make tests compile

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* remove unused

* remove unused event stuff

* Adds proper validation-worker to make integration tests work

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* import saturating

* remove panic test

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Amar Singh <asinghchrony@protonmail.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Bastian Köcher <info@kchr.de>

test/service/src/lib.rs

@@ -162,6 +162,7 @@ where
 		} else {
 			polkadot_service::IsCollator::No
 		},
+		None,
 	)
 	.map_err(|e| match e {
 		polkadot_service::Error::Sub(x) => x,
@@ -546,3 +547,22 @@ impl TestNode {
 		self.client.wait_for_blocks(count)
 	}
 }
+
+/// Run a relay-chain validator node.
+///
+/// This is essentially a wrapper around
+/// [`run_validator_node`](polkadot_test_service::run_validator_node).
+pub fn run_relay_chain_validator_node(
+	task_executor: TaskExecutor,
+	key: Sr25519Keyring,
+	storage_update_func: impl Fn(),
+	boot_nodes: Vec<MultiaddrWithPeerId>,
+) -> polkadot_test_service::PolkadotTestNode {
+	polkadot_test_service::run_validator_node(
+		task_executor,
+		key,
+		storage_update_func,
+		boot_nodes,
+		Some(cumulus_test_relay_validation_worker_provider::VALIDATION_WORKER.into()),
+	)
+}