net-p2p/prowlarr: Add new port

Prowlarr is an indexer manager/proxy built on the popular *arr .net/reactjs
base stack to integrate with your various PVR apps.
Prowlarr supports management of both Torrent Trackers and Usenet Indexers.
It integrates seamlessly with Lidarr, Mylar3, Radarr, Readarr, and Sonarr
offering complete management of your indexers with no per app Indexer setup
required (we do it all).