We already have a pattern for navigation folders and searching for
templates – let’s use it for the copy page too. And I reckon we can
represent services as folders if the user has multiple services they
could copy a template from.
Since you can now see them when searching you should also be able to
select and move them. Which means that they needed to be included in
the `Form`’s list of possible choices of things to move.
The Jinja template for the ‘choose templates’ page is now pulling in
data from a lot of diparate places in order to work out what to show. As
we add more logic about what to show (in order to make the live search
work) it’s going to get harder to have all this logic in the Jinja
template.
This commit refactors it back into Python where we have more language
features for managing complex logic.
It’s a bit weird to call this file a model, in that it’s dealing with
some presentational logic, rather than just data. Conceptually it’s more
like a view model[1].
1. https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93viewmodel
