Add bindings for CapsFeatures
https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstCapsFeatures.html
Manually written (because miniobject), see caps.rs, sample.rs, etc.
Support needs to be added to caps.rs
https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstCapsFeatures.html
Manually written (because miniobject), see caps.rs, sample.rs, etc.
Support needs to be added to caps.rs