[General,Core,Applications] Last finishing of application form.

* Adds select2 jquery plugin via composer.
* Modifies form handling javascript to cope with select2.
* Adds new ViewHelper FormSelect to handle translation of placeholder values.
* Adds german translations
* Fixes some bugs in summary-form empty summary notices.
* Moves Summary form edit button hover handling to css.
* Fixes some quirks in form related view scripts.