Add BannerRandom filter to erbium

I'm attempting to investigate two issues in parallel:
1) How many of our requests are served uncompressed
2) Does it take longer to serve requests further down in the slot chain

This should only need to run for a couple of days to get the sample data
to look at.

Change-Id: I62e682596c07e293d7d910f6cc7be63482aa7975