MLECO-2874: Move NMS out of the OD use_case

* Add ImageUtils
* Move image related code from UseCaseCommonUtils to ImageUtils
* Move NMS related code to ImageUtils
* Delete test specific ImageUtils and use new ImageUtils

Signed-off-by: Richard Burton <richard.burton@arm.com>
Change-Id: Icbf5dd9c6a941b0126ecdf69a0c9d9969f22729f
diff --git a/tests/use_case/vww/InferenceVisualWakeWordModelTests.cc b/tests/use_case/vww/InferenceVisualWakeWordModelTests.cc
index 04dce0d..194099f 100644
--- a/tests/use_case/vww/InferenceVisualWakeWordModelTests.cc
+++ b/tests/use_case/vww/InferenceVisualWakeWordModelTests.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022 Arm Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -34,7 +34,7 @@
     memcpy(inputTensor->data.data, imageData, copySz);
 
     if(model.IsDataSigned()){
-        convertImgIoInt8(inputTensor->data.data, copySz);
+        arm::app::image::ConvertImgToInt8(inputTensor->data.data, copySz);
     }
 
     return model.RunInference();