Lint: try swapping to djlint

[agjohnson]

We are currently using djhtml here for html formatting. This package only does part of what djlint does, but was providing nicer html formatting when I first tried both. I did try djlint recently and the formatting was mostly okay. I think we could swap to djlint if we wanted to, as djlint does have some more checks on templates.

Some things to evaluate:

• Template indentation and formatting looks okay/better with djlint?
• djlint catches easy to miss things like multiline, single line comments ({# #}), maybe HTML errors?
• djlint catches/fixes other issues?

This will be a disruptive change, so would hopefully be an obvious choice after playing with djlint a bit more.