multimedia/vlc: Make UPNP a default OPTION

Rationale: UPNP / DLNA is a widespread way of serving media via various
off-the-shelf NAS devices, and also with our own port of minidlna. It's
well suited to be included in the official VLC package.

PR: 260617
Reported by: hellocodebsd@gmail.com
MFH: 2022Q2