Add support for Jinja templates

[markhobson]

This repository currently provides Nunjucks templates for JavaScript projects. It would be useful to also provide Jinja templates to support Python projects.

The syntax is identical and I have successfully copy & pasted the Nunjucks template into a Python Flask app. The question is how best to support this setup in a maintainable way? Ideally a pip package like govuk-frontend-jinja is to govuk-frontend would be provided.

[alex9smith]

Thanks @markhobson! We'd talked internally about how we might want to handle other templating languages but we didn't expect it to come up quite so quickly in reality. This is on our roadmap to investigate more in the future, so the suggestion of the pip package is much appreciated.

[markhobson]

No problem! Happy to help once you decide how best to proceed.