Add RKNN / Object Detection Pipeline (#1144)

Tested on Orange Pi 5 and Cool Pi 4B. Merge with parts of the OpenCV DNN PR. 

Adds support for YOLOv5s models for Rockchip CPUs with a NPU. Right now hard coded to a note model from alex_idk. Very much still incubating and largely untested.

.styleguide

@@ -18,6 +18,7 @@ modifiableFileExclude {
   \.dll$
   \.webp$
   \.ico$
+  \.rknn$
   gradlew
 }