Initial version of Call::decode dispatch. (#300)

* Initial version of call dispatch.

* cargo fmt --all

* Remove unused stuff.

* cargo fmt --all

* weight is part of msg + events

* should_fail_on_weight_mismatch

* plug into runtime

* cargo fmt --all

* fix benchmarks compilation?

* expected/actual values in events

* return actual weight from MessageDispatch::dispatch()

* MessageOrigin -> InstanceId + move bridge_account_id to bp-runtime

* fix benchmarks again

* cargo fmt --all

* clippy

Co-authored-by: Svyatoslav Nikolsky <svyatonik@gmail.com>

bridges/primitives/message-dispatch/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "bp-message-dispatch"
+description = "Primitives of bridge messages dispatch modules."
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+
+[dependencies]
+bp-runtime = { path = "../runtime", default-features = false }
+codec = { package = "parity-scale-codec", version = "1.3.1", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"bp-runtime/std",
+	"codec/std",
+]