Implemented file upload backend functionality

 - Implemented FileUploadController
 - Added jquery form plugin for handling form submissions in the background using ajax
(including files)
 - Added apache commons io library as dependency in pom file
 - Activated CommonsMultipartResolver with file size limit of 1MB

JIRA:
CG-21
Cleanup of image upload and integration into recipe formulars

 - Cleanup
 - Integrate file upload into add- and edit-forulars for recipes

JIRA:
CG-21
Merge branch 'fileupload'