Dockerizing

## What does this PR do?
This PR adds a Dockerfile and fig file for easier development with the help of Docker. 
It is open for discussion and any comments are appreciated.
If someone is unfamiliar with: [fig](http://fig.sh/) or [docker](https://www.docker.com).
Using fig is much easier than using docker directly but might be replaced with a direct way in docker soon. 
### Possible Discussion/Changes
The pavement script could be replaced with additions into the docker file and another container running GeoServer. 
I did not tackle this just yet because I wanted to make sure you guys would like to have a dockerized way.
## Changes
### Added
Option for start action of pavement script to run django in foreground. This is needed for Docker to detect something is running and does not quit. 
Dockerfile added to install all dependencies into the docker container.
Fig file for easier development, starting of docker etc.
### Changed
Update Readme
### Removed