Add Dockerfile with uploader dependencies bundled

This may or may not be helpful with getting people's environments
setup to use the uploader. The Dockerfile creates an image that contains
all of the dependencies (OS package and Python level) for the uploader
to function.

To build the image:

cd eventdata
docker build -t "azavea/hunchlab-examples" .

To run the image:

docker run -ti "azavea/hunchlab-examples" /bin/bash
root@651942713f17:/app# python upload.py -c config.ini data/test-2rows.csv