Support for Bridging ERC-20 on OP Stack chains

[albertlai431]

To reach feature parity with optimism-sdk (https://docs.optimism.io/builders/app-developers/tutorials/cross-dom-bridge-erc20), viem should support deposits and withdrawals of ERC-20 tokens

Discord discussion: https://discord.com/channels/1156791276818157609/1156791519089541241/1303035693349601310

[gndelia]

I implemented the depositing/withdrawing of ETH/ERC20 tokens on a fork of OP or a webapp.

Using the Portal contract did not work, at least with the old version of OP. So I had to use a custom implementation for depositing and initiating withdrawals for ERC20, using the L1StandardBridge and the L2Bridge. In case anyone needs it, here is the deposit and the withdrawal.

We may eventually move this into a publishable package