MLECO-3186: Each use case should same namespace convention as KWS and ASR

Certain UCs required additional work due to case context variables which also
became part of a namespace in generated files.
Solution was to declare these extra variables as part of the UC namespace in the respective model.hpp files.
Additional changes to standardise use of namespaces may be required - proposing new task.

Minor typo and rewording of customizing.md in relevant sections included.

Signed-off-by: Liam Barry <liam.barry@arm.com>
Change-Id: Ie78f82a30be252cb841136ea5115f21fc8d762cb
diff --git a/source/application/api/use_case/object_detection/include/YoloFastestModel.hpp b/source/application/api/use_case/object_detection/include/YoloFastestModel.hpp
index 4c64433..16d0715 100644
--- a/source/application/api/use_case/object_detection/include/YoloFastestModel.hpp
+++ b/source/application/api/use_case/object_detection/include/YoloFastestModel.hpp
@@ -19,13 +19,16 @@
 
 #include "Model.hpp"
 
-extern const int originalImageSize;
-extern const int channelsImageDisplayed;
-extern const float anchor1[];
-extern const float anchor2[];
-
 namespace arm {
 namespace app {
+    namespace object_detection {
+        extern const int originalImageSize;
+        extern const int channelsImageDisplayed;
+        /* NOTE: anchors are different for any given input model size, estimated during training
+         * phase */
+        extern const float anchor1[];
+        extern const float anchor2[];
+    } /* namespace object_detection */
 
     class YoloFastestModel : public Model {