[Add] Clip Operator

-Implemented forward and backward CPU kernels for the Clip operator.

-Added support for optional attributes (min and max).

-Created unit tests for forward and backward kernels, as well as for various ways to set the attributes.

See Issue:aidge_quantization#38 (closed)

include/aidge/backend/cpu/operator/ClipImpl.hpp

+/********************************************************************************
+ * Copyright (c) 2023 CEA-List
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ ********************************************************************************/
+
+#ifndef AIDGE_CPU_OPERATOR_CLIPIMPL_H_
+#define AIDGE_CPU_OPERATOR_CLIPIMPL_H_
+
+#include <cstddef>  // std::size_t
+#include <memory>
+#include <tuple>    // std::tuple
+#include <vector>
+#include <algorithm>
+
+#include "aidge/backend/cpu/operator/OperatorImpl.hpp"
+#include "aidge/operator/Clip.hpp"
+#include "aidge/utils/Registrar.hpp"
+#include "aidge/utils/Types.h"
+#include "aidge/backend/cpu/data/GetCPUPtr.h"
+
+
+namespace Aidge {
+// Operator implementation entry point for the backend
+    using ClipImpl_cpu = OperatorImpl_cpu<Clip_Op,
+    void(float, //Forward Types
+    float, 
+    const void*,
+    const std::size_t, 
+    void*),
+    void(float,//Backward Types
+    float, 
+    const std::size_t,
+    const void*, 
+    const void*,
+    void*)>;
+
+    REGISTRAR(Clip_Op,"cpu",Aidge::ClipImpl_cpu::create);
+}  // namespace Aidge
+
+#endif /* AIDGE_CPU_OPERATOR_CLIPIMPL_H_ */