feat!: start paying a symbolic amount for transactions

[AlicanC]

Resolves #159

• We had a bunch of APIs that required signerOrProvider but only accepted Provider. All of these were renamed to walletOrProvider and updated to accept Wallet | Provider. The reasoning is: these APIs require paying fees. While signing is enough on Ethereum, we need the full wallet functionality so we can pick the right coins too.

• Contract deployment and calling now require a Wallet that has enough balance. (1 per transaction ATM) In tests, seeding wallets are required:

  /*** Before ***/
  
  const provider = new Provider('http://127.0.0.1:4000/graphql');
  
  // Deploy contract
  const factory = new ContractFactory(bytecode, abi, provider);
  const contract = await factory.deployContract();
  
  /*** After ***/
  
  const provider = new Provider('http://127.0.0.1:4000/graphql');
  
  // Create and seed wallet
  const wallet = Wallet.generate({ provider });
  await seedWallet(wallet, [{ assetId: NativeAssetId, amount: 1 }]);
  
  // Deploy contract
  const factory = new ContractFactory(bytecode, abi, wallet);
  const contract = await factory.deployContract();