Relayer using a queue to scale up requests

[hashmesan]

Motivation

Current design will not handle high request gracefully. That is due to the issue with serializing requests through the blockchain, causing request that came later to time out. We should use a queue like bullmq to separate the request/queueing vs the submitting to blockchain, then respond back on a streaming channel (HTTP stream).

Design

Build a stress test simulator for devnet and verify behaviors.

user request -> [queue] -> process on account A (nonce_A)
                        \--> process on account B (nonce_B)
                         |---> process on account C (nonce_C)