Implements #182

Implements #182 

Implements configuration and a set of client-side helpers to render Graphite graphs of event history in bootbox modal popups with configurable time ranges for events on /monitoring/events. Comments in public/javascripts/graphite-helpers.js describe its usage and needed configuration parameters. Example configuration parameters are present in config/index.js

Note that, if config.graphiteEvent.enabled != true, nothing will be rendered in /monitoring/events from this PR. config.graphiteEvent.enabled = false by default in the included config/index.js