More comprehensive identity system (#4326)

* Initial prototype

* Work on test harness.

* Minor removal

* Add some tests

* Fix tests

* More tests

* Final tests

* General documentation

* Function-level docs.

* Function-level docs.

* Identity fields.

* Fix dependency

* Docs

* Spelling nits

* Address grumbles.

Cargo.toml

@@ -63,6 +63,7 @@ members = [
 	"frame/finality-tracker",
 	"frame/generic-asset",
 	"frame/grandpa",
+	"frame/identity",
 	"frame/im-online",
 	"frame/indices",
 	"frame/membership",

frame/identity/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "pallet-identity"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+serde = { version = "1.0.101", optional = true }
+codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
+enumflags2 = { version = "0.6.2" }
+rstd = { package = "sp-std", path = "../../primitives/sr-std", default-features = false }
+runtime-io = { package = "sp-io", path = "../../primitives/sr-io", default-features = false }
+sp-runtime = { path = "../../primitives/runtime", default-features = false }
+support = { package = "frame-support", path = "../support", default-features = false }
+system = { package = "frame-system", path = "../system", default-features = false }
+
+[dev-dependencies]
+primitives = { package = "sp-core",  path = "../../primitives/core" }
+balances = { package = "pallet-balances", path = "../balances" }
+
+[features]
+default = ["std"]
+std = [
+	"serde",
+	"codec/std",
+	"rstd/std",
+	"runtime-io/std",
+	"sp-runtime/std",
+	"support/std",
+	"system/std",
+]