[WIP] Verify streamed orderbook

[nlordell]

This PR adds a new script a streamed orderbook and periodically checks that it matches the on-chain version of the orderbook.

This will hopefully give us some confidence about the new streamed orderbook implementation.

Test Plan

It is the test!

npx truffle exec --network mainnet scripts/verify_streamed_orderbook.js

[nlordell]

Fiber bundles

A "fiber" is lightweight thread of execution made up of promises. This is different than a background thread which would require a Worker and is more heavy-weight.