[TASK] Create example event listeners for finality events on different chains

[drewstone]

Overview

We should extend event listeners with more examples. Lower level listeners for blocks/etc.

Do not change the API unless you have explicit blueprint services that would benefit from these examples. Moreover, just demonstrate the experience of using the EventListener trait to build new extensions.

• [TASK] Event listener hook into Reth Extensions (https://github.com/paradigmxyz/reth-exex-examples/blob/main/in-memory-state/src/main.rs) and extend with many examples.
• [TASK] Event listener for Ethereum finality events
• [TASK] Event listener for Tangle (Substrate) finalized blocks
• [TASK] Event listener for L2 finalized state / blocks (Arbitrum, Optimism).

[yurixander]

@tbraun96 This task might be on the wrong repo, might need to transfer it 👀