Samples - Add a sample for decoding a video and converting the raw decoded YUV frames to RGB format using HIP kernels (#108)

* WIP: class implementation

* add more definitions

* rocvideodecode implementation

* formatting fixes

* address review comments

* rocvideodecode class update

* videodec sample app-enable all apis

* video_dec_rgb_sample implementation

* fix issue with release mode execution and other clean_up

* add copyright block

* address review comments

* sync with tot and addressed review comments

* convert to snake_case

[ROCm/rocdecode commit: 15fb3e0b91]

projects/rocdecode/samples/videoDecodeRGB/README.md

@@ -0,0 +1,11 @@
+# Video Decode Sample
+This sample illustrates the FFMPEG demuxer to get the individual frames which are then decoded using rocDecode API and optionally color-converted using custom HIP kernels on AMD hardware. This sample converts decoded YUV output to one of the RGB or BGR formats(24bit, 32bit, 464bit)
+
+## Build and run the sample:
+```
+mkdir build
+cd build
+cmake ..
+make -j
+./videodecodergb -i <input video file - required> -o <optional; output path to save decoded YUV frames> -d <GPU device ID, 0 for the first device, 1 for the second device, etc> -of <optional: output format bgr, bgra, bgr48, bgr64 etc>
+```