Add a multidimensional wrapper around c-array

[rrsettgast]

This allows for better use of compile time known dimension c-arrays, and provides indexing accessors that take a parameter pack.

note...after a while I wondered why I didn't just replicate the interface of std::mdspan or rather std::mdarray coming in c++23, but you can't really anyways since they overload the operator[] to follow something like:

template< typename ... INDICES>
constexpr inline T& operator[]( INDICES ... indices)

which you can't do until c++23.

We can certainly replicate the dependence on std::extents, which is also c++23 but functionally simple if we don't try to do a bunch with dynamic_extents.

[wrtobin]

Only two small things we can remove, other than getting the cuda builds passing this looks solid.