Improve Array/View Conversion API Consistency

[Sichao25]

PCMS currently handles multiple array and view types, including Kokkos views, mdspan, and Omega_h arrays. On the Python API side, we also need to support NumPy arrays and potentially device-side arrays such as Torch tensors in the future.

It would be helpful to have a consistent and clean API for converting between these different array types to mdspan of varying dimensions — similar to how Kokkos provides to_mdspan() as a unified interface for most use cases. Utilities for converting between different array types would also be helpful if there are any use cases in the future.

Currently, a few such conversion functions exist in utility/arrays.h but they do not form a consistent API.

This also address issue #190 .

[jacobmerson]

Couldn't agree more with this comment. This is a consistent issue and there are lots of places that this inconsistency causes a lot of unnecessary copies.

What I had in mind is as follows:

1. Use MDSpans (we have our ArrayView aliases) for non-owning data
2. Anywhere we expect to have ownership, we should use Kokkos views

I would be open to considering Kokkos::View for non-owning views if that presents a big benefit, but this could be swapped out in our ArrayView alias to test. I do like that MDSPan will eventually be part of the C++ standard and if used for public facing APIs could ingest any data, not just from Kokkos-based applications.

We should provide overloads for our make_array_view that takes the standard array types we work with.