Migrating Template Engine

[Fiery]

There were discussions about template engines and swig made it through all that to be the choice, however with swig "no longer maintained" (https://github.com/paularmstrong/swig/issues/628), looks like eventually it will reach the point to consider migrating swig to other alternatives.
I do like jinja style templating and I am also aware of some other young engines that has good benchmarks, like slm, dust, while veterans like handlebar, mustache and ejs are also good. But just to keep consistent and eliminate labor work on all html files, maybe nunjucks would be worth checking out?

[knownasilya]

I think we will go for a more traditional engine like Handlebars, especially to prevent too much logic creeping into the templates, which is currently a problem.