Add frame-metadata from substrate.

frame-metadata/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "frame-metadata"
+version = "12.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Decodable variant of the RuntimeMetadata."
+readme = "README.md"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "1.3.4", default-features = false, features = ["derive"] }
+serde = { version = "1.0.101", optional = true, features = ["derive"] }
+
+[features]
+default = ["std", "v12"]
+v12 = []
+std = [
+	"codec/std",
+	"serde",
+]