Updated qbittorrentvpn.md with configuration for ProtonVPN (Wireguard)

[bosskie]

The current qbittorrentvpn.md had installation settings only for PIA VPN.

I've added a seperate method for ProtonVPN which is quite different from PIA VPN.

How I achieved this method ? Please refer this documentation [HERE] (https://github.com/binhex/documentation/blob/master/docker/faq/vpn.md) from binhex. Scroll down to Q31/A31, where it was explained in detail.