feat: add support for Metamask snap

[bajpai244]

We now have a very good working metamask-snap for Starknet. It can be a great way to onboard new users to starknet, without requiring them to install a new wallet to just try out a dApp.

We should add Metamask as an option as well here, i.e the ability for a dApp to connect with metamask snap as the starknet wallet.

This will require a wrapper { we can discuss whether it should live here, or as a seperate npm package }, the wrapper should be able to wrap the metamask injected provider, and embed a starknet wallet provider in the window object, and that should allow us to add metamask to UI, and be able to send transactions via it.