This CL moves the pointer and reference files over to type/ and updates
the namespaces.
Bug: tint:1718
Change-Id: I487a37ef2f6a3884d2ff51af4ac63869c3e03698
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/113420
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>