List Tokens From User Accounts

[dOrgJelli]

Currently we have hard-coded balance checks for ETH, USDC, and WBTC. We need a way to show all balances of tokens held by an account at the start of a run, and at the end. This will require a 3rd party service, so making this feature optional would be ideal. If the API key isn't present simply show the hardcoded list.