RFC: gstreamer: Add an element proc macro based on the `gobject` crate to ease GStreamer element implementation
This implementation is based on the gobject crate which we probably want to get in upstream gtk-rs
but I already started to experiment to properly in the gstreamer-rs
infrastructure so that it becomes even simpler to implement GStreamer elements in Rust.
This implements an gstreamer::element
proc macro which allows declaring a GStreamer element subclass (or a subclass of the subclass obviously) and lets us define all the necessary element metadata as part of the macro metadata, namely:
- Factory related metadatas
- Pad templates
- Debug category which is automatically registered