Add Table class and use it in ItemArray

Table is a bi-dimensional version of Array

Use Kokkos::SubView to access rows and columns of Tables which are
Array's

Do not use SubArray (to be removed) anymore to get a partial views of
an Array, but Kokkos::SubView. The reason for this change is that
SubArray were not a safe construction since the underlying Array could
be destroyed (or resized) while the SubArray was still active. This
has obviously an extra cost, but Kokkos developers have made the
mechanism so that reference counters are deactivated (for all
Kokkos::View) during parallel_for. Thus performances are the same but
this new approach is safer.
[Now one use the subArray() function to get a View on a part of an Array.]