COMPMID-2452: Add mnist example

* Add small-mnist example
* Add PrintAccessor
* Add DequantizationLayer graph node

Change-Id: I7bc8011e5a602f40fa3c47b231a2a69c804e78c2
Signed-off-by: Isabella Gottardi <isabella.gottardi@arm.com>
Reviewed-on: https://review.mlplatform.org/c/2274
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Giorgio Arena <giorgio.arena@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/arm_compute/graph/frontend/Layers.h b/arm_compute/graph/frontend/Layers.h
index 120997a..61cd83c 100644
--- a/arm_compute/graph/frontend/Layers.h
+++ b/arm_compute/graph/frontend/Layers.h
@@ -489,6 +489,25 @@
     const QuantizationInfo _weights_quant_info;
     const QuantizationInfo _out_quant_info;
 };
+/** Dequantization Layer */
+class DequantizationLayer final : public ILayer
+{
+public:
+    /** Construct a dequantization layer.
+     *
+     */
+    DequantizationLayer()
+    {
+    }
+
+    NodeID create_layer(IStream &s) override
+    {
+        NodeParams  common_params = { name(), s.hints().target_hint };
+        NodeIdxPair input         = { s.tail_node(), 0 };
+        return GraphBuilder::add_dequantization_node(s.graph(), common_params, input);
+    }
+};
+
 /** DetectionOutput Layer */
 class DetectionOutputLayer final : public ILayer
 {
@@ -555,7 +574,7 @@
 class DummyLayer final : public ILayer
 {
 public:
-    /** Construct an input layer.
+    /** Construct a dummy layer.
      *
      * @param[in] shape Output shape
      */