Add React Hook and Context to Simplify UX

[matiasbenary]

This PR adds a Wallet Selector Context Provider (WalletSelectorProvider) and a React Hook (useWalletSelector) that simplify initializing the wallet selector and using it on React applications

Note: This PR only adds a new package, currently it shows 18 files changed only because it is based on add-new-api (#1276 )

[gagdiez]

very excited about this simpler interface!

import '@near-wallet-selector/modal-ui/styles.css';
import { setupMyNearWallet } from '@near-wallet-selector/my-near-wallet';
import { setupMeteorWallet } from '@near-wallet-selector/meteor-wallet';
import { WalletSelectorProvider } from '@near-wallet-selector/react-hook';

const walletSelectorConfig = {
  network: "testnet",
  createAccessKeyFor: "hello.near-examples.testnet",
  modules: [
    setupMyNearWallet(),
    setupMeteorWallet(),
  ],
}

export default function App({ Component }) {
  return (
    <WalletSelectorProvider config={walletSelectorConfig}>
      <Component {...pageProps} />
    </WalletSelectorProvider>
  );
}

[trechriron]

Amazing