Add GridSample impl for 1D and 2D

Implementation for the GridSample Operator.

include/aidge/backend/cpu/operator/GridSampleImpl.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_GRIDSAMPLEIMPL_H_
+#define AIDGE_CPU_OPERATOR_GRIDSAMPLEIMPL_H_
+
+#include <array>
+#include <memory>
+#include <tuple>
+#include <vector>
+
+#include "aidge/backend/OperatorImpl.hpp"
+#include "aidge/operator/GridSample.hpp"
+#include "aidge/utils/Registrar.hpp"
+#include "aidge/utils/Types.h"
+#include "aidge/backend/cpu/data/GetCPUPtr.h"
+
+namespace Aidge {
+
+// compute kernel registry for forward and backward
+class GridSampleImpl1DForward_cpu
+    : public Registrable<GridSampleImpl1DForward_cpu,
+                         std::tuple<DataType, DataType>,
+                         void(const GridSample_Op&,
+                            const std::shared_ptr<Tensor>&,
+                            const std::shared_ptr<Tensor>&,
+                            const std::shared_ptr<Tensor>&)> {};
+
+class GridSampleImpl2DForward_cpu
+    : public Registrable<GridSampleImpl2DForward_cpu,
+                         std::tuple<DataType, DataType>,
+                         void(const GridSample_Op&,
+                            const std::shared_ptr<Tensor>&,
+                            const std::shared_ptr<Tensor>&,
+                            const std::shared_ptr<Tensor>&)> {};
+
+class GridSampleImpl_cpu : public OperatorImpl {
+   public:
+    GridSampleImpl_cpu(const GridSample_Op& op) : OperatorImpl(op, "cpu") {}
+
+    static std::unique_ptr<GridSampleImpl_cpu> create(const GridSample_Op &op) {
+        return std::make_unique<GridSampleImpl_cpu>(op);
+    }
+
+   public:
+    Elts_t getNbRequiredProtected(const IOIndex_t inputIdx) const override final;
+    void forward() override;
+};
+
+namespace {
+// add cpu backend to GridSample_Op<1> implementation registry
+static Registrar<GridSample_Op> registrarGridSampleImpl_cpu("cpu", Aidge::GridSampleImpl_cpu::create);
+}  // namespace
+
+}  // namespace Aidge
+
+#endif /* AIDGE_CPU_OPERATOR_GRIDSAMPLEIMPL_H_ */