Feat/balance manipuration

[shunsukew]

Resolve #65

User's free balance manipuration.
Because

1. balance logic is inside runtime (Only extrinsic can modify the state)
2. Anyone needs be able to manipulate balances without creating sig & extrinsic (tx fee should not be charged).

Solution here is creating unsigned extrinsic and put it in transaction pool when RPC method is called.

Custom logic added to balances_pallet

For balance manipulation, some custom logic are added to the original pallet_balances (polkadot-v0.9.39).
※ Comment out [swanky node specific] is added to those custom implementations. source code under frame/balances/src other than [swanky node specific] is copied from Substrate.

1. set_free_balance call
   This is almost same as set_balance. While set_balance alters free_balance and reserved_balance only allowed by RootOrigin, set_free_balance alters free_balance only unless account itself is removed due to Existential Deposit and operation is only allowed by NoneOrigin so that it can accept UnsignedExtrinsic.
2. validate_unsigned
   Because set_free_balance uses Unsigned Extrinsic, we need validate_unsigned implementation in balances pallet to check validity of them.

How to set free balance

Example Request

curl http://localhost:9933 -H "Content-Type:application/json;charset=utf-8" -d   '{                                                                                 feat/balance-manipuration ✭ ✱
     "jsonrpc":"2.0",
      "id":1,
      "method":"balance_setFreeBalance",
      "params": ["5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY", 120000000000000000000, null]
    }'

Example Response

{"jsonrpc":"2.0","result":null,"id":1}% 

How to get account info via custom RPC

Example Request

curl http://localhost:9933 -H "Content-Type:application/json;charset=utf-8" -d   '{                                                                                 feat/balance-manipuration ✭ ✱
     "jsonrpc":"2.0",
      "id":1,
      "method":"balance_getAccount",
      "params": ["5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY", null]
    }'

Example Response

{"jsonrpc":"2.0","result":{"free":120000000000000000000,"reserved":0,"misc_frozen":0,"fee_frozen":0},"id":1}%

[codespool]

I couldn't build on mac.
got:

error: failed to run custom build command for `libp2p-core v0.38.0`

Caused by:
  process didn't exit successfully: `/Users/sasapul/Work/astar/swanky-node/target/release/build/libp2p-core-6cc3b51ab4deb7e5/build-script-build` (exit status: 101)

[shunsukew]

failed to run custom build command for `libp2p-core

Some Substrate's current prerequisites seem not to be installed. You need to install them. I think protoc is the one.
https://docs.substrate.io/install/troubleshoot-rust-issues/#installing-cmake-or-protobuf-for-m1-macos-users
https://substrate.stackexchange.com/questions/4015/failed-to-run-custom-build-command-for-libp2p-core-v0-34-0