Including Reusable templates into pages

[shawninder]

In Kirby, you'll notice we can customize the navigation header and footer. We can also insert these reusable sections into any page we create. But the frontend needs a way to get the data that is to be shown in those sections, and the way we're doing this is Kirby doesn't quite work. See https://github.com/tjikko-studio/components/pull/121

[shawninder]

This is almost ready, I expect when we're done merging the templatesContent and Headers-related branches, this should be pretty much done.

[ktryndchrs]

@shawninder I think it is done