Docker image for tools

[barthanssens]

Create a docker image for all the BeST python tools (not the pelias) + dependencies like pandas and other required libraries.

Challenge: make it as small as possible, e.g. starting from the official Python docker image 3.7.4-alpine3.10.

One probably has to add gcc, makefile etc... but they should be removed afterwards, in the same RUN command (see also https://developers.redhat.com/blog/2016/03/09/more-about-docker-images-size/)

Downloading and file processing should be done outside the docker container (i.e. add VOLUME so the docker guest can mount a directory on the docker host)