Base Dockerfile for CoMSES Net images, extends from https://github.com/phusion/baseimage-docker

Using the phusion baseimage-docker image for runit support and other rationale detailed in their README

Latest release targets Ubuntu 22.04

Also installs the basic Python natural language toolkit (NLTK) data for stopwords and punkt

• https://www.nltk.org/data.html
• https://www.nltk.org/_modules/nltk/tokenize/punkt.html