dev-util/test: reorganize utility packages

Reorganise utility packages finder and metadata so that both
cros-test-finder and testexecserver can use them.

BUG=b:200620228
TEST=./fast_build.sh -T; sudo emerge cros-test-finder test-exec-server; cros-test-finder; testexecserver ...

Cq-Depend: chromium:3195231
Change-Id: Ie69c9e56e2a4f359c5c5f83e0b14a5e9ea67f332
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/3194863
Reviewed-by: Jesse McGuire <jessemcguire@google.com>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
Tested-by: Seewai Fu <seewaifu@google.com>
Commit-Queue: Seewai Fu <seewaifu@google.com>
6 files changed