Improve Storage Classes concept page

[sftim]

This is a Feature Request

What would you like to be added
Improve Storage Classes to make the content easy to follow, and to guide people to other pages if it's helpful to read those first.

Why is this needed
Kubernetes' storage documentation is not that easy to understand, and it's an area of Kubernetes that is hard to practice without building a working cluster that includes many features (for example: CSI drivers, multiple nodes, node- or network-attached storage, multiple namespaces, and more).

Comments
/sig storage

[k8s-ci-robot]

This issue is currently awaiting triage.

SIG Docs takes a lead on issue triage for this website, but any Kubernetes member can accept issues by applying the triage/accepted label.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.