feat: create wallet flow

[seanmc9]

analogous to the Sign Up/Log In flow that is very common in web2, this feature would be having a wallet icon in the top right instead of connect wallet that lets you then pick between "Create Wallet" and "Connect Wallet" when you click on it.

Connect Wallet would be the same button and function it is today, no need to mess with rainbowkit there.

But the Create wallet would kickstart the Coinbase Wallet creation (and later, once they've shipped Apple Pay funding, funding flow after creation, but that's a separate ticket) flow, so a user makes a wallet.