Lenet operators

Added backend_cuda for the following operators:

• AvgPooling
• FC/Gemm
• MaxPooling
• ReLU

include/aidge/backend/cuda/operator/FCImpl.hpp

@@ -47,7 +47,7 @@ public:
     // ~FCImpl_cuda();
 
 private:
-    template <class T> void forward_(const Tensor& input0, const Tensor& input1, const Tensor& input2, bool noBias, DimSize_t outChannels);
+    template <class T> void forward_(const Tensor& input0, const Tensor& input1, const Tensor& input2, bool noBias, std::size_t outChannels);
 };
 
 namespace {