Jinja2 templates should be prettified

[ross-spencer]

As they get more complex then it will benefit the reader, and the developer to have a consistent and objective way to format these without too much to think about.

Unibeautify comes from the Atom IDE plugins and has a nice HTML format plugin that on face value can handle the templates without too much issue. If JavaScript is imported and CSS external too then that a separate format utility can be used for that and it will help improve readability.

There is a code playground here: https://playground.unibeautify.com/

Another nice feature is that now Unibeautify has been moved out of Atom is is standalone and can be run locally via NPM and also integrated into Git CI processes.

[mcantelon]

I've created a work-in-progress PR to use djlint for linting/formatting.

#302