Documentation Updates

### Problem description

We would like to update our documentation. We would like to foster communication between the team and the community to make sure the docs included all of the best and none of the rest!! 🥷

### Solution description

We are researching the other client docs and will incorporate the most important sections from each to create a complete set of docs for Lodestar and the broader consensus client ecosystem.

### Additional context

Lodestar Docs: https://chainsafe.github.io/lodestar
Lighthouse Docs: https://lighthouse-book.sigmaprime.io/
Prysm Docs: https://docs.prylabs.network/docs/getting-started
Teku Docs: https://docs.teku.consensys.net/
Nim Docs: https://nimbus.guide/

Begin with the Lodestar Docs site and compare its coverage with the linked Lighthouse, Prysm, Teku, and Nim documentation. Identify the sections most relevant to Lodestar and the broader consensus client ecosystem; the work is done when the selected documentation updates are incorporated and the resulting set is complete and coherent.

Written by the indexing model from the issue text.