OZG-5981 OZG-6154 Show caption when loading file

alfa-client/libs/binary-file/src/lib/binary-file2-container/binary-file2/binary-file2.component.html

 <ods-attachment
   [caption]="file.name"
+  [loadingCaption]="file.name + ' wird geladen...'"
   [description]="file.size | fileSizePlain"
   [fileType]="getIconType(file.contentType)"
   (click)="downloadFile()"