Add LogEntries Daemon and tasks to follow system and application logs

* LogEntries is a service for viewing and managing your system logs
  online (http://logentries.com)
* Involves setting up an agent and daemon to collect and transmit the
  logs in the background
* Apps/sites, tools, and servers should choose what logs to send up on
  an individual basis.
  * follows the convention `X-logentries`, which indicates that the
    following role will setup logentries to track X.
  * This is similar to `X-nginx`, where the `nginx` role is tasked w/
    setting up Nginx, while `x-nginx` is responsible for configuring
    Nginx for a specific application (e.g: `staticsite-nginx`)
* External apps and services have their keys defined in `var.yml`