Decide what to do about Python code

[mmmaaatttttt]

Problem description:

Related to #14 but different. The Python files in the models folder are Python2, old and in need of an update. Feels a bit strange to have Python files in here, but I'd be ok with an upgrade to Python3 or a re-implementation in node instead.

Suggested solution:

If we stay in python, we'll need to:

• upgrade to v3
• add requirements
• remove code by using packages (eg https://pypi.org/project/num2words/ and beautifulsoup)

if we move to node, we'll need to

• add cheerio as a dependency
• migrate each file to JS

We should break this up into sub-issues, but not until we make a decision about JS vs Python.