Before we were using glob, which was about to start failing on subdirectories in views (which we started using in `conference`). Instead of searching for `l10n.json`, it seemed more appropriate to instead look for localization by using the configured pages that need to be localized.
This moves all locale/translation building to a dependency, `scratch-www-intl-loader`, as well as tests associated with it. Also gets rid of the `make translations` step.
1. Load locale strings into `window._messages` in a separate file added to `template.html`, which contains view-specific and general strings
2. Update build-locales to compile separate files