Rewrite of EventLogging module

This commit is the first in a series of commits that aim to comprehensively
refactor the EventLogging Puppet module. The refactoring migrates process
management of EventLogging daemons from Supervisord to Upstart and abstracts
site-specific configurations out of the module itself. The best Puppet modules
use Puppet abstractions to provide a mini-DSL for managing a service class, and
that is what I have attempted to do here. The module provides a suite of four
custom resource types. Each type corresponds to a particular kind of daemonized
actor that performs some data processing step by transforming the event stream
in some definite way. These resources can be freely composed into a data
processing pipeline. The provisioned services are glued together using a
publisher/subscribe messaging pattern over TCP/IP, which can scale to an
arbitrary number of instances on an arbitrary number of hosts.

This change provides the bulk of the implementation and most of the
clean-up.

Change-Id: Iba8cc5d7b121e3e0dd5b557523022c7aa9824f58
Merge "Rewrite of EventLogging module" into production