Global `Web3Context`, connect wallet functionality and connect wallet UI

[Dhaiwat10]

Checklist

• Global Web3Context which will provide different utilities to your app through the <Provider />. The utilities would enable easy access to information like - whether a wallet is connected or not, the network the wallet is connected to, etc.
• Utility functions like requestNetworkChange, requestWalletConnection, etc.
• Connect wallet buttion and any other UI pieces necessary.

Notes

Try to re-use existing solutions like web3modal.

[Dhaiwat10]

Closing via #76