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/TypePrinter.h b/arm_compute/graph/TypePrinter.h
index 131fd39..7610852 100644
--- a/arm_compute/graph/TypePrinter.h
+++ b/arm_compute/graph/TypePrinter.h
@@ -83,6 +83,9 @@
         case NodeType::DeconvolutionLayer:
             os << "DeconvolutionLayer";
             break;
+        case NodeType::DequantizationLayer:
+            os << "DequantizationLayer";
+            break;
         case NodeType::DetectionOutputLayer:
             os << "DetectionOutputLayer";
             break;