add Edda and property template

There is a fresh binary build of Edda cached on GitHub as a release, much like was done for Asgard.

This commit adds the Dockerfile and an edda.properties template.

The container was successfully tested with a test AWS account.

I put together some documentation here: https://github.com/Netflix/edda/wiki/Docker-Start-Guide.  This page includes a Vagrantfile with a configuration suitable for testing the container on Ubuntu 14.04.

The run command will look like this:

```
docker run -d --name edda -p :8080:8080 -v `pwd`/edda.properties:/tomcat/webapps/ROOT/edda.properties netflixoss/edda:2.1
```