Organize template methods

[caprilesport]

I feel like the methods are now well written in the templates module.
Lots of methods are tied to paths, which does not let me unit test them.
Maybe some functions (or just one) like from_path should exist, and all the rest
should be handled by the template struct.

Beyond that, I think I need to organize the new select functions, add the core parts
as methods for the appropriate structs.