Reland "Metal: Add labels to help with GPU Debugging"

Original change's description:
> Metal: Add labels and debug groups to help with GPU Debugging.
>
> * Adds SK_ENABLE_MTL_DEBUG_INFO to enable labels and debug groups,
>   dependent on skia_enable_gpu_debug_layers.
>
> Bug: skia:12150
> Change-Id: I5b4538c0f6df6ceed72d7e8e6f1952fd193b7b90
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/422756
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>

Bug: skia:12150

Change-Id: I4bc686b7fdb1b929dbfdb2dd12fb5170fc9b36a2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/425185
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
14 files changed