Revise the installation guide

## Overview

In the introduction to the installation instructions, briefly describe why a user should prefer using one installation procedure over another. Distinguish between production installations and local clusters for development or demo purposes. Include a link to the page for setting up a local cluster.

Consider separating the install procedures and putting each on its own separate page.

Audience: Standalone Operator

Type: Task

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://github.com/etcd-io/website/blob/main/content/en/docs/v3.5/install.md