Move hardware information to separate article, add index information, fix WSL docs not being included

[username223]

This PR:

• Moves information on how to connect the boards from Windows and Linux quickstart guides to their own articles. Currently only the Pine64 BL602 EVB ver 1.1 and the Boufallo Lab dev boards are included. I plan on adding images + instructions for the remaining Pine64 form factors when they arrive.
• Adds a short introductory text to the landing page.
• Fixes the WSL Quick Start documentation not being included at all.

First two bullet points work towards issue https://github.com/pine64/bl602-docs/issues/51.

[username223]

I've also added a guide on connecting the Pinenut-01S using the USB programmer.

Images are from https://imgur.com/gallery/vnZIxCQ and https://imgur.com/gallery/Srte22N, used with permission.

CC: https://github.com/pfeerick, owner of images used.

[gamelaster]

Looks great, thank you 😊