IVGCVSW-6856 Add GATHERNd FrontEnd and Ref Implementation

* Add front end
* Add reference workload
* Add unit tests
* Add EndToEnd test

Signed-off-by: Teresa Charlin <teresa.charlinreyes@arm.com>
Change-Id: I4cebd17b18476df86162e2dda3366c10e80bd2f8
diff --git a/Android.mk b/Android.mk
index b91fd9c..0dd593a 100644
--- a/Android.mk
+++ b/Android.mk
@@ -224,6 +224,7 @@
         src/armnn/layers/FloorLayer.cpp \
         src/armnn/layers/FullyConnectedLayer.cpp \
         src/armnn/layers/GatherLayer.cpp \
+        src/armnn/layers/GatherNdLayer.cpp \
         src/armnn/layers/InputLayer.cpp \
         src/armnn/layers/InstanceNormalizationLayer.cpp \
         src/armnn/layers/L2NormalizationLayer.cpp \