File selector update - Small updates to the frontend placeholder website - Fixed some z-index values in the filemanager stylesheet - Added styling for selected items that will be previewed when using the file selector - Added a seperate popup layer for the file selector so other popups can be used while in the selector - Fixed bug for the collection content type that would cause the value of inputs to disappear - Added support for file selector in the FileManager object and created fileSelector object that will handle the file selector by using the FileManager object - API endpoint 'filemanager' with the action 'verify-files' now also returns 'existingFiles' with complete data of the files. Before it would only return the id's