[bazel] Move icu to //bazel/icu/

Like Freetype, this creates a new icu_utils Bazel workspace
so we can copy in the make_data_cpp.py script and the
convenience SkLoadICU* files.

Change-Id: I7f777b0e0bc9a74a8e132a87b052d55f6dae0326
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/558732
Reviewed-by: Ben Wagner <bungeman@google.com>
8 files changed