Fix for spaces between locales in app.conf

In short, I just replaced the space chars with empty space inside `AppConf.java`.

Talked about changing `getLocales()` to return a List<String> object but this leads to a big refactor across 12+ files and that doesn't even include the `ContentPlugin` which is happy to use locales in it's params as String vargs.

It's a little controversial (to break the `ContentPlugin`) so I've made the minimal changes needed for this use case to work (with tests added).