doc: link to Jinja1 is broken

[florentx]

the link to Jinja1 is broken in the documentation.
http://jinja.pocoo.org/docs/faq/#why-is-there-no-python-2-3-support

[DasIch]

The entire section could probably be deleted.

[florentx]

I agree 👍

A bit of history might be added somewhere, if it does not exist.