Resolve "Implement UploadArea"

...java/de/uniwue/swp/sshtool/database/DBConnectionImpl.java

development/gui/config.conf

...i/src/main/java/de/uniwue/swp/dragdropssh/gui/Colors.java

...de/uniwue/swp/dragdropssh/gui/DragDropSSHApplication.java

...main/java/de/uniwue/swp/dragdropssh/gui/SceneManager.java

.../uniwue/swp/dragdropssh/gui/dialog/DialogPopupHelper.java

.../uniwue/swp/dragdropssh/gui/dialog/login/LoginDialog.java

.../uniwue/swp/dragdropssh/gui/scene/InitializableScene.java

...e/uniwue/swp/dragdropssh/gui/scene/login/LoginScreen.java

.../swp/dragdropssh/gui/scene/operation/OperationScreen.java

.../gui/scene/operation/components/AbstractFileSelector.java

...dropssh/gui/scene/operation/components/TransferArrow.java

...ragdropssh/gui/scene/operation/components/UploadArea.java

...dropssh/gui/scene/operation/components/tree/FileTree.java

development/gui/src/main/resources/messages_en_US.properties

...e/uniwue/swp/dragdropssh/management/ManagementFacade.java

...iwue/swp/dragdropssh/management/ManagementFacadeImpl.java

...iwue/swp/dragdropssh/management/command/CloseCommand.java

...e/swp/dragdropssh/management/command/DownloadCommand.java

...wp/dragdropssh/management/command/RetryUploadCommand.java