Implement PrivateVPN proxy provider

[rlaphoenix]

Is your feature request related to a problem? Please describe.
PrivateVPN supports proxies almost exactly like NordVPN, just with a lot fewer available servers and countries.

Describe the solution you'd like
It should implement it almost exactly like NordVPN, but grab server information via https://privatevpn.com/serverlist/

Describe alternatives you've considered
N/A

Additional context
N/A