fix: set an address for authrpc to the op-rbuilder readme

[therustmonk]

This PR fixes the launch instructions for op-rbuilder, making the AuthRPC accessible on all network interfaces. This is necessary to allow op-rbuilder to be reachable from the virtual network interface created by Docker.

Additionally, the metrics port has been changed to 9011, since 9001 is used by builder-playground for the beacon:

go run main.go cook opstack --external-builder http://host.docker.internal:4444
2025/04/23 20:21:02 Log level: info
2025/04/23 20:21:02 Genesis block hash: 0x301f9f301f868d587fec26c2a1b5f7d9896736842ab1787923722c3213b61e05
true

========= Services started =========
- el (authrpc: 8551/8551, http: 8545/8545, rpc: 30303/30303)
- beacon (http: 3500/3500, p2p: 9000/9000/udp, p2p: 9000/9001, quic-p2p: 9100/9100)
- validator ()
- rollup-boost (authrpc: 8551/8552)
- op-node (http: 8549/8549, metrics: 7300/7300, p2p: 9003/9003, p2p: 9003/9004/udp)
- op-geth (authrpc: 8551/8553, http: 8545/8546, metrics: 6061/6061, rpc: 30303/30304, ws: 8546/8547)
- op-batcher ()

========= Output =========
- op-geth-enode: enode://3479db4d9217fb5d7a8ed4d61ac36e120b05d36c2eefb795dc42ff2e971f251a2315f5649ea1833271e020b9adc98d5db9973c7ed92d6b2f1f2223088c3d852f@127.0.0.1:30304?discport=0

Trailing spaces have also been removed in some places.

[Copilot]

Pull Request Overview

This PR updates the op-rbuilder launch instructions in the README to ensure AuthRPC is accessible on all network interfaces and to change the metrics port to avoid conflicts with builder-playground.

• Updated AuthRPC parameters to include --authrpc.addr 0.0.0.0 for external access.
• Changed metrics port from 9001 to 9011.
• Removed trailing spaces in the file.