Improve approach to i18n property files in wicket

ATM we have properties xml for each component in wicket.
Although this makes it decoupled and isolated it makes it very difficult to add new languages as we need to add many new property files.

Wicket supports application level property file (it has to be named after the name of our application which is StorefrontApplication). According to documentation https://cwiki.apache.org/confluence/display/WICKET/Everything+about+Wicket+internationalization all is needed is to add this property file next to java class.

Potentially we may also explore IResourceSettings class and have this file per theme