Replace Handlebars with Tera

[XAMPPRocky]

As a half step towards using Zola it would be to replace the current handlebars templates with Tera. This would make the followup PR a lot smaller, and would allow us to do more in the templates themselves.

[tshepang]

Hm, why the move to Zola? I suppose there's a discussion someplace.

[XAMPPRocky]

@tshepang There hasn’t been much public discussion, it’s mainly been me talking to the other maintainers. I do intend to write a motivation explaining why, but the TL;DR is that I don’t want to continue to maintain something bespoke when there’s more actively maintained solutions that provide more functionality. Why Zola specifically? Well there are features that the rust website needs that none of the static site generators currently have, and the Zola maintainers were open to adding those features. https://zola.discourse.group/t/zola-www-rust-lang-org/328

[tshepang]

Alright, wasn't aware that the blog used something bespoke. Is it the plan to replace the whole site (with zola), or just the blog?

[XAMPPRocky]

The website is a much larger project and I don't want to make any promises, though I would certainly like for the website to be static. Right now I'm focusing on the blog as it's much smaller and limited in scope.