* Added wireguard.svg.
* Added WireGuard icon to README.md.
Added reference image to images/reference/wireguard.svg and updated images/reference/index.md correspondingly.
* Corrected the Aria label for wireguard.svg. This added 5 bytes to the size; updated README.md correspondingly.
Co-authored-by: Terence Eden <edent@users.noreply.github.com>
