Replace jinja2 with mako

[TheJJ]

trafficstars

Due to personal experience I'd really like to replace jinja2 with mako templates instead.

We only use jinja in openage/codegen/coord.py.

Really not high priority :)

[Brodan]

Hi, I'm a newbie looking to contribute and this looks like a cool first issue that I can actually wrap my head around. Any chance the hacktoberfest label can be added so it could count towards my contributions?

[heinezen]

@Brodan Sure, you can go for it :)