Port to trapperkeeper 0.3.0

This commit updates PuppetDB to use the new trapperkeeper 0.3.0
API.  This includes:

* Slightly modified syntax for defining services and service
  lifecycle behavior
* Switch from log4j to logback, update documentation and packaging
  accordingly
* Switch from jetty7 to jetty9
* Add example of how to use "reloaded" interactive development pattern
  in REPL