Matmul rework

The behavior of the reworked MatMul on the arguments in the following way.
- If both arguments are 2-D they are multiplied like conventional matrices.
- If either argument is N-D, N > 2, it is treated as a stack of matrices residing in the last two indexes.
Exp: For the MatMul of tensor A of shape (3,3,2) with tensor B of shape (3,2,4), A is a stack of three 2D matrices each of shape (3,2), and B is a stack of 3 2D matrices, each of shape (2,4).

unit_tests/data/Test_TensorImpl.cpp

@@ -80,12 +80,11 @@ TEST_CASE("Tensor fill") {
       {11,12,13,14,15}}
     });
     // expectedTensor->print();
-    
+
     REQUIRE(*concatenatedTensor == *expectedTensor);
   }
 }
 
-
 TEST_CASE("[backend_cpu/data] Tensor(methods)", "[Tensor]") {
   Tensor x = Array3D<int, 2, 2, 2>{{
     {{1, 2},