Use Gstreamer Buffer map in StreamCapture

[edgarriba]

After discussion: https://discourse.gstreamer.org/t/zero-copy-video-frames/3856/2

This pull request includes several changes to improve the functionality and reliability of the stream capture pipeline in the kornia-io crate. The most significant changes involve updating dependencies, introducing a new FrameBuffer struct, and modifying the StreamCapture implementation to use this new struct. Additionally, there are minor changes to example files to ensure proper mutability of capture objects.

Updates and Dependency Changes:

• Updated gst and gst-app dependencies to version 0.23.4 in Cargo.toml.

Stream Capture Improvements:

• Introduced a new FrameBuffer struct to store the frame buffer, width, and height.
• Modified the StreamCapture struct to include a last_frame field, which is an Arc<Mutex<Option<FrameBuffer>>>.
• Updated the StreamCapture::new method to set callbacks on appsink for capturing new samples and storing them in last_frame.
• Changed the StreamCapture::grab method to retrieve the last frame from last_frame and convert it to an Image.
• Refactored the extract_frame_buffer method to extract a FrameBuffer from the AppSink.

Error Handling:

• Added a new LockError variant to the StreamCaptureError enum to handle errors when locking the last_frame mutex.

Example Code Adjustments:

• Updated various example files to ensure capture objects are mutable by using let mut instead of let. [1] [2] [3] [4] [5]