feat: integration test

[anna-carroll]

on a loop

• sends a transaction to the target chain
• waits for it to mine
• sleeps

while collecting metrics on mine time

---

env vars

RPC_URL=target chain RPC URL
CHAIN_ID=target chain ID
AWS_KMS_KEY_ID=any KMS key funded on the target chain 
RECIPIENT_ADDRESS=the address of the recipient of the Ether
SLEEP_TIME=60 (or whatever)

[dylanlott]

LGTM