Setup papertrail for logs with a number of people who can have access

[AutomatedTester]

It would be good to have an easy way for people to see what is happening on the relevant systems when ./wpt is running. This will allow us to view when things go wrong and be able to fix it.

[jeffcarp]

I think what should happen is:

• Have all WPT runs send their output to Stackdriver
• Anyone with read access to the GCP project will then have access

(We can give you read access @AutomatedTester)

[jgraham]

A simpler alternative would be to just upload the raw.log files we use for creating the results to the place we store the json data, and link to per-run logs somewhere in the UI. This seems simpler to set up than the above alternatives, and provides the full data (at least from inside wpt) for analysis.