Rename Ganesh-based SkImage and SkSurface and relocate to src/gpu/...

This will make it easier to partition the Ganesh backend and
make things more modular.

FYI: This will require a manual G3 roll due to the renamed
targets used by the vulkan build.

Change-Id: I0af38e5b3b5ab65ac5d58fa454fe754f06b1601a
Bug: skia:13983
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/661458
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
57 files changed