[autotest] Add label detection using tool avtest_label_detect

A new label detection function is added in CrosHost to include labels detected
by tool avtest_label_detect.

BUG=chromium:338336
TEST=atest host create 172.22.30.146
confirm the host has label webcam created.

Change-Id: I11bd4fb41e866baf6d089e82f102a747368831e7
Reviewed-on: https://chromium-review.googlesource.com/202042
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Kuang-che Wu <kcwu@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
1 file changed