multimedia/gstreamer1-qt: Mark DEPRECATED and set EXPIRATION_DATE

This project was abandoned 10 years ago and doesn't serve a purpose
in the ports tree anymore, especially since we on kde@ are trying to
politely shoo Qt5 out the door.

multimedia/gstreamer1-qt/Makefile

@@ -13,6 +13,9 @@ WWW=		https://gstreamer.freedesktop.org/
 LICENSE=	LGPL21+
 LICENSE_FILE=	${WRKSRC}/COPYING
 
+DEPRECATED=		Project abandoned 10 years ago
+EXPIRATION_DATE=	2024-10-22
+
 LIB_DEPENDS=	libboost_thread.so:devel/boost-libs \
 		libgstreamer-1.0.so:multimedia/gstreamer1