feat(gst): enhance GStreamer integration with new modules and improved API

This commit introduces significant enhancements to the GStreamer integration by:
- Adding new modules for bins, caps, elements, pads, and plugins
- Implementing a more ergonomic API with helper methods like play(), pause(), ready()
- Adding support for various GStreamer plugins including app, autodetect, playback, and videoconvertscale
- Improving error handling with better context attachment
- Updating dependencies to latest versions including gstreamer-video 0.24.4
- Refactoring existing code to use modern Rust patterns and features

gst/src/plugins/videoconvertscale/videoconvert.rs

@@ -0,0 +1,49 @@
+use crate::*;
+#[doc(inline)]
+pub use gstreamer_video::VideoFormat;
+
+#[repr(transparent)]
+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 }
+    }
+}
+
+impl Sink for VideoConvert {}
+impl Source for VideoConvert {}
+
+impl VideoConvert {
+    pub fn new(name: impl AsRef<str>) -> Result<Self> {
+        use gstreamer::prelude::*;
+        let element = gstreamer::ElementFactory::make("videoconvert")
+            .name(name.as_ref())
+            .build()
+            .change_context(Error)
+            .attach("Failed to create videoconvert element")?;
+        Ok(VideoConvert { inner: element })
+    }
+
+    // pub fn with_caps(mut self, caps: &gstreamer::Caps) -> Self {
+    //     use gstreamer::prelude::*;
+    //     self.inner.set_property("caps", caps);
+    //     self
+    // }
+    pub fn with_output_format(self, format: VideoFormat) -> Result<Self> {
+        use gstreamer::prelude::*;
+        let caps = Caps::builder(CapsType::Video)
+            .field("format", format.to_str())
+            .build();
+        self.inner.set_property("caps", &caps.inner);
+        // .change_context(Error)
+        // .attach("Failed to set output format on videoconvert")?;
+        Ok(self)
+    }
+}