Edge refactor

• Refactor edge detection pipeline sample.
• Add bench for edge detection pipeline.

juno_samples/edge_detection/benches/edge_detection_bench.rs

@@ -64,10 +64,12 @@ fn edge_detection_bench(c: &mut Criterion) {
 
     let mut r = runner!(edge_detection);
 
+    let frames: Vec<_> = (0..num_frames).map(|_| load_frame(&mut video)).collect();
+
     group.bench_function("edge detection bench", |b| {
         b.iter(|| {
             for i in 0..num_frames {
-                let frame = load_frame(&mut video);
+                let frame = &frames[i];
                 let ptr = frame.ptr_def().unwrap() as *const f32;
 
                 assert!(frame.rows() as usize == height);