Add cleanup_crates.py for finding unused dev-rust ebuilds.

BUG=None
TEST=./cleanup_crates.py -c --log-level=debug

Cq-Depend: chromium:2342113
Change-Id: Ic7e7b76397846b23404b1988c049b104d9df3170
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2339312
Tested-by: Allen Webb <allenwebb@google.com>
Commit-Queue: Allen Webb <allenwebb@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed