Add missing features to Sink trait

There are various other features (specifically virtual methods and their arguments) that GstBaseSink has and we don't wrap yet. This should probably come with adding support for libgstbase in gstreamer-rs: Might make sense to do this first: https://github.com/sdroege/gstreamer-rs/issues/7

Most of these features can be wrapped basically 1-1: https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseSink.html