IVGCVSW-4210 Create a public API for the common backend files

 * Create a public API for the common backend files
 * Move OutputHandler to armnn internal
 * Remove unused headers

Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I3e86d908b021e3561befa9d45158d87d2cbb18c0
diff --git a/src/backends/backendsCommon/TensorHandleFactoryRegistry.cpp b/src/backends/backendsCommon/TensorHandleFactoryRegistry.cpp
index 4692b9f..0670461 100644
--- a/src/backends/backendsCommon/TensorHandleFactoryRegistry.cpp
+++ b/src/backends/backendsCommon/TensorHandleFactoryRegistry.cpp
@@ -3,9 +3,8 @@
 // SPDX-License-Identifier: MIT
 //
 
-#include "TensorHandleFactoryRegistry.hpp"
-#include "IMemoryManager.hpp"
-
+#include <backendsCommon/TensorHandleFactoryRegistry.hpp>
+#include <armnn/backends/IMemoryManager.hpp>
 
 namespace armnn
 {