Add NextDNS Application

[officiallymarky]

I like to hot link the configuration page of my NextDNS account. Would be nice to have a pre-built application option for NextDNS.

Logo: https://user-images.githubusercontent.com/33408375/194485696-a77639b8-9e02-402a-b729-6177768c6830.png

Color: #05A

Site: https://nextdns.io