EZP-23199: As a developer, I want to be able to override and add new Handlebars templates

JIRA: https://jira.ez.no/browse/EZP-23199

# Description

As the title suggests, this story is about changing the Handlebars templates handling so that it's possible to inject custom templates or override the existing ones.

# Tasks

* [ ] Get some reviews on the document
* [ ] Change the `Y.eZ.TemplateBasedView` to use the template registry
* [ ] Moved the Handlebars templates and write the custom controller to automatically wrap the templates in a YUI module
* [ ] Write the dump script
* [ ] [Optionally] Pre-compile the template before dumping to the disk