Investigate smaller Docker image

[ramhiser]

The Docker image is currently 881.1MB (see below). Can we make this smaller? Possible solutions:

• Use different base image
• Use Alpine

REPOSITORY             TAG             IMAGE ID            CREATED             SIZE
ramhiser/spark         2.0.0           6c67e7d3b81b        About an hour ago   881.1 MB
spark                  latest          6c67e7d3b81b        About an hour ago   881.1 MB