Support Coinbase Wallet

[osis]

Is your feature request related to a problem? Please describe.
Working of the thoughts in #8. Coinbase Wallet's has been making large strides in terms of adoption which means that many dapps will want to validate functionality. It's maturity level in terms of features, compared to the current Metamask wallet adapter, this makes it the perfect candidate for the first new wallet to integrate the adapter.

Describe the solution you'd like
The wallet interfaced mapped to Coinbase wallet functionality.

Describe alternatives you've considered
Looked at a few different options like Rainbow Wallet & Trust Wallet. In terms of features and general adoption, Coinbase Wallet wins. Would be cool to look into these as follow ups though.