Catches events, stores them in the database to be queried via API.
run cp .default.env .env, and add your own private key as RELAYER_ECDSA_KEY in .env. You need to be running a MySQL instance, and replace all the MYSQL_ env vars with yours.
Run go run cmd/main.go --help to see a list of possible configuration flags, or go run cmd/main.go to run with defaults, which will process messages from L1 to L2, and from L2 to L1, and start indexing blocks from 0.