Add Sound Devices page to FAQ

Hello,

Currently the sound devices page is only linked from the Getting Started page as "A reasonable audio device, sound card and/or mic ([see this list](https://jamulus.io/kb/2021/01/05/Jamulus-Sound-Devices.html) for examples)"

I recommend adding a link to the page from somewhere more visible, such as the FAQ list. This would hopefully make the page easier to find.

Thanks!

Locate the FAQ list in the Jamulus website and review the existing Sound Devices page linked from Getting Started. Add a visible FAQ link to that page, then verify the FAQ renders correctly and the link opens the intended page.

Written by the indexing model from the issue text.