Puppetize supervisor configs for EventLogging

This change puppetizes the EventLogging supervisor configuration, currently
running on vanadium.

This could be made a lot nicer. Ideally we'd have custom resource types for
supervisor-managed programs that generate a job-config file and plop it into
/etc/supervisor/conf.d. (<https://github.com/plathrop/puppet-module-supervisor>
looks like a good generic implementation.)

It may even be desirable to have resource types or classes corresponding to the
different EventLogging daemons.

I intend to do that (...seriously, I do), but my goal is to first have the
setup 100% puppetized, and then iterate on abstractions.

Change-Id: I256d613f48e54afb9df5fa031d3f98288caab796