Chore: Substrate based node with ocw pallets

[SHA888]

• node
• pallet ocw
• runtime

[syoumoku]

Clone From https://github.com/jimmychu0807/substrate-offchain-worker-demo
Which is a demo to fetch cryptocurrency prices using off-chain workers.

Substrate Off-chain Worker Demo

This repository is built based on Substrate Node Template v3.0.0+monthly-2021-10.

The purpose is to demonstrate what off-chain worker could do, and how one would go about using it.

Run

1. First, complete the basic Rust setup instructions.

2. To run it, use Rust's native cargo command to build and launch the template node:

cargo run --release -- --dev --tmp

3. To build it, the cargo run command will perform an initial build. Use the following command to
   build the node without launching it:

cargo build --release

Since this repository is based on Substrate Node Template,
it's README
applies to this repository as well.

About Off-chain Worker

• The core of OCW features are demonstrated in pallets-ocw, and
  pallets-example-offchain-worker.

  Note that in order for the offchain worker to run, we have injected Alice key in
  node/service.rs

• Goto docs/README.md to learn more about off-chain worker (extracted from Substrate
  Recipes, based on Substrate v3).

• Review the code of Offchain Worker Example Pallet within Substrate
  and its rustdoc.
  This pallet is also added in this repository.

[syoumoku]

Same issue met when compiling the ocw-demo from substrate recipes
JoshOrndorff/substrate-recipes#480