[dawn][wire] Use MemoryHandle instead of Read/WriteHandle

A few changes that were difficult to do separately from the
usage of MemoryHandle in wire/{client, server} were:

 - Make DeserializeCreateRead/WriteHandle optional now that they are no
   longer used inside of Dawn. They will be removed once the Chromium
   implementation is deleted.
 - Use `std::byte` in dawn_wire.json for the serialized handle
   creation data and data updates: this matches the interface of
   MemoryHandle and avoids the need from conversions from spans of
   uint8_t to spans of std::byte. (required adding `std::byte` as a
   native type in dawn.json).
 - Change ChunkedCommandSerializer CommandExtensions to take a
   span<std::byte> instead of a void* (further spanification is in a TODO).
 - Change server::MapUserData to use size_t for offset and size, the use
   of uint64_t was a leftover from a time when the MapAsync arguments
   where using uint64_t.

Changes that make use of MemoryHandle are:

 - Implement MemoryHandle in both Client/ServerInlineMemoryTransferService.
 - Implement MemoryHandle in both Client/ServerMemoryTransferService_mock.
 - Use MemoryHandle instead of WriteHandle in client/Queue.cpp and
   ServerQueue.cpp.
 - Use a single MemoryHandle in client::Buffer instead of both ReadHandle
   and WriteHandle.
 - Use a single MemoryHandle in server::BufferMapState.
 - Update WireMemoryTransferServiceTests mock calls to expect
   MemoryHandle calls instead.

Bug: 492456046, 524776858, 512465980, 524406299, 526537224, 526537254, 526549345
Change-Id: I3097d65bc282e93d75e53adf241221b146d32460
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/317635
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Loko Kung <lokokung@google.com>
Reviewed-by: Shao, Jiawei <jiawei.shao@intel.com>