feat: Restructure the gst parent<->child relations

gst/src/plugins/videoconvertscale/videoconvert.rs

@@ -1,22 +1,9 @@
-use crate::*;
+use crate::priv_prelude::*;
 #[doc(inline)]
 pub use gstreamer_video::VideoFormat;
 
-#[repr(transparent)]
-#[derive(Debug, Clone)]
-pub struct VideoConvert {
-    inner: gstreamer::Element,
-}
-
-impl IsElement for VideoConvert {
-    fn as_element(&self) -> &Element {
-        unsafe { core::mem::transmute(&self.inner) }
-    }
-
-    fn into_element(self) -> Element {
-        Element { inner: self.inner }
-    }
-}
+wrap_gst!(VideoConvert, gstreamer::Element);
+parent_child!(Element, VideoConvert);
 
 impl Sink for VideoConvert {}
 impl Source for VideoConvert {}