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
```