copybot: Move copybot to infra/copybot

BUG=b:394397748
TEST=CQ

Cq-Depend: chromium:6238746
Change-Id: Ibf0d4032c40445957a88c789d8492f480f83a866
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/6238744
Tested-by: Jonathon Murphy <jpmurphy@google.com>
Commit-Queue: Jonathon Murphy <jpmurphy@google.com>
Reviewed-by: Jeremy Bettis <jbettis@chromium.org>
8 files changed