Downstream node-template pull (#9915)

* downstream node template pull: README updated, add shell.nix

* consistant cargo.toml style

* Update bin/node-template/shell.nix

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

substrate/bin/node-template/shell.nix

@@ -0,0 +1,35 @@
+let
+  mozillaOverlay =
+    import (builtins.fetchGit {
+      url = "https://github.com/mozilla/nixpkgs-mozilla.git";
+      rev = "57c8084c7ef41366993909c20491e359bbb90f54";
+    });
+  pinned = builtins.fetchGit {
+    # Descriptive name to make the store path easier to identify
+    url = "https://github.com/nixos/nixpkgs/";
+    # Commit hash for nixos-unstable as of 2020-04-26
+    # `git ls-remote https://github.com/nixos/nixpkgs nixos-unstable`
+    ref = "refs/heads/nixos-unstable";
+    rev = "1fe6ed37fd9beb92afe90671c0c2a662a03463dd";
+  };
+  nixpkgs = import pinned { overlays = [ mozillaOverlay ]; };
+  toolchain = with nixpkgs; (rustChannelOf { date = "2021-09-14"; channel = "nightly"; });
+  rust-wasm = toolchain.rust.override {
+    targets = [ "wasm32-unknown-unknown" ];
+  };
+in
+with nixpkgs; pkgs.mkShell {
+  buildInputs = [
+    clang
+    pkg-config
+    rust-wasm
+  ] ++ stdenv.lib.optionals stdenv.isDarwin [
+    darwin.apple_sdk.frameworks.Security
+  ];
+
+  LIBCLANG_PATH = "${llvmPackages.libclang}/lib";
+  PROTOC = "${protobuf}/bin/protoc";
+  RUST_SRC_PATH = "${toolchain.rust-src}/lib/rustlib/src/rust/library/";
+  ROCKSDB_LIB_DIR = "${rocksdb}/lib";
+
+}