Consider making distinct types for pinned and unpinned arrays

There are operations that can't support unpinned arrays, but currently the types don't actually prevent such arrays from being provided. There are constructive operations that should be able to produce either pinned or unpinned arrays, but currently only exist for unpinned arrays, such as primArrayFromList (there's no pinnedPrimArrayFromList).

One potential option would be to make a type parameter that is a data kind, indicating Pinned or Unpinned. Then operations that apply to both can just leave that type parameter unspecified...