CandidateBackingSubsystem (#1312)

* Updates guide for CandidateBacking

* Move assignment types to primitives

* Initial implementation.

* More functionality

* use assert_matches

* Changes to report misbehaviors

* Some fixes after a review

* Remove a blank line

* Update guide and some types

* Adds run_job function

* Some comments and refactorings

* Fix review

* Remove warnings

* Use summary in kicking off validation

* Parallelize requests

* Validation provides local and global validation params

* Test issued validity tracking

* Nits from review

Cargo.toml

@@ -50,6 +50,7 @@ members = [
 	"node/overseer",
 	"node/primitives",
 	"node/service",
+	"node/core/backing",
 	"node/subsystem",
 	"node/test-helpers/subsystem",
 	"node/test-service",

node/core/backing/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "polkadot-node-core-backing"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+futures = "0.3.5"
+log = "0.4.8"
+sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "master" }
+keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "master" }
+primitives = { package = "sp-core", git = "https://github.com/paritytech/substrate", branch = "master" }
+
+polkadot-primitives = { path = "../../../primitives" }
+polkadot-node-primitives = { path = "../../primitives" }
+polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
+erasure-coding = { package = "polkadot-erasure-coding", path = "../../../erasure-coding" }
+statement-table = { package = "polkadot-statement-table", path = "../../../statement-table" }
+futures-timer = "3.0.2"
+streamunordered = "0.5.1"
+derive_more = "0.99.9"
+bitvec = { version = "0.17.4", default-features = false, features = ["alloc"] }
+
+[dev-dependencies]
+sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
+futures = { version = "0.3.5", features = ["thread-pool"] }
+subsystem-test = { package = "polkadot-subsystem-test-helpers", path = "../../test-helpers/subsystem" }
+assert_matches = "1.3.0"