[TABJS-4] Allow generic signer

[dtbuchholz]

Summary

Wagmi is one of the most used front end libraries. Under the hood, it uses viem, which can be viewed as an alternative to ethersjs. It might be beneficial to create a generic Signer interface that lets the developer pass either an ethersjs or viem account, making it easier to use the SDK without custom viem<>ethers adapters. (This was a request from someone during ETHOnline.)

_{From SyncLinear.com | TABJS-4}