Update Node architecture

[bradleycamacho]

Description

Cleaner path, diagram needs to be upgraded with op-supervisor, and make it clear that l2geth is only for OP Mainnet.

https://docs.optimism.io/operators/node-operators/architecture

Action items

1. Do research on topic and raise any questions with the docs team
2. Write a first draft. It doesn't have to be worded perfectly as the docs team will review
3. Ping @bradleycamacho or @krofax on discord and request review
4. Implement feedbacks from @bradleycamacho and @krofax
5. Publish