[Applications, Core] Adds DraftableEntityInterface.

* a draftable entity is an entity which can be saved uncompleted, it is marked with a
  flag.
* Modifes Application Repository to ignore entity drafts on normal queries.

Conflicts:

	[solved] module/Applications/src/Applications/Entity/Application.php
	[solved] module/Applications/src/Applications/Repository/Application.php
[Auth] Adds AnonymousUser entity.
[General] composer: Adds "blueimp/jquery-file-upload" to dependency list.
[Core]: Adds FormContainer, Modifies Core\Form\Form for use in FormContainer.
[Auth] Sets default role "guest" in AnonymousUser.
[Auth] Modifies UserProfile formulars for use in FormContainer
[Applications] Modifies formulars for use in container.
[Core] Adds FormContainer and SummaryForm.
[Auth] Use FormContainer for user profile formular.
[Applications] Creates Apply Formular Container.
[Applications,Auth,Core] Fix formular containers, spinnerbutton
[Applications,Auth,Core] Adds file upload formular and implements strategies for handling uploaded files.
[Applications,Auth,Core] Adds social profiles form to apply container.

- Adds some inline documentation by the way.
[Applications,Core] Refactores FileUpload formulars, adds ImageUpload formular, MultiFileUpload formular.
[Applications,Core] Adds Attributes entity for application and adds to apply form.

Additionally, makes some bugfixes and cleanups mainly in *\Form namespaces
[Applications] Adds application preview.
[Applications] Abort or Send application and post processing (send mails).
[Applications,Core] Disclaimer checkbox (privacy policy), small fixes and improvements on the success page
[All] Fixes form handling in all modules.

Also fixes user image copy (when logged in user applies to a job).
[Core,Applications,Auth] Adds german translations.