Revise the FAQ

## Overview

The longer explanations in the FAQ might be better as part of conceptual information -- for example, in the system or architecture overview. Retain the short answers that don't fit elsewhere. The FAQ can contain links to further information in other sections.

Audience: All

Type: Conceptual

The existing documentation might contain helpful source material that you can pull into this doc change. See recommendations for the existing (at the time of the CNCF tech doc analysis) etcd technical documentation pages:
https://github.com/cncf/techdocs/blob/main/assessments/0010-etcd/etcd-implementation.md/#general-reorganization

## 🎤 Context

This issue tracks recommended changes resulting from an analysis of the etcd documentation commissioned by CNCF. The analysis and supporting documents are here: https://github.com/cncf/techdocs/tree/main/assessments/0010-etcd/

## ✌️ Possible Implementation

Related material in the current doc:
- https://etcd.io/docs/v3.5/faq/