docs: add local storage support

[Vicente-Cheng]

Related: harvester/harvester#5724

[Vicente-Cheng]

I will work on the https://docs.harvesterhci.io/v1.3/host/#multi-disk-management to link both LonghornV2/LVM volumes.
The multi-disk management update PR: #664

cc @tserong, @jillian-maroket, @bk201

[github-actions]

Name	Link
🔨 Latest commit	8cde017
😎 Deploy Preview	https://672c5a0c0393340177383c0c--harvester-preview.netlify.app

[tserong]

LGTM, thanks!

(I did notice one or two little wording things like "You can refer Multi-Disk Management for how to add disks" should be "You can refer to Multi-Disk Management...", and I think we generally have a preference for spelling out "virtual machine" in full rather than using "VM", but @jillian-maroket is going to do a much better job of reviewing the wording than I am, so I didn't add any inline comments on this stuff.)

[jillian-maroket]

I rewrote and restructured all of the sections, and added content where necessary. Another round of edits may be necessary after you respond to my comments.

[jillian-maroket]

I suggest removing all mentions of backup creation for now. PTAL at the new note in the last section.