Dashboard: Log the number of rows created
Dashboard: Log the number of rows created

This lets us monitor the number of rows we're processing/creating from
the Dashboard, through Stackdriver Log-based Metrics. It's also helpful
to use this information in debugging upload processing issues.

R=f07c55753dac44d78e0294a1d64ea321baaa78f4@google.com, fancl@chromium.org

Change-Id: I0587ebb5decb7b09779ae27972a12c88b370572c
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/2181994
Auto-Submit: Dean Berris <34a37f59e4ade3cf49221306f04217acf3e86255@chromium.org>
Commit-Queue: Andrew Bennetts <f07c55753dac44d78e0294a1d64ea321baaa78f4@google.com>
Reviewed-by: Andrew Bennetts <f07c55753dac44d78e0294a1d64ea321baaa78f4@google.com>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult