Added more translation strings

There are some quite tricky ones which are hardly translateable.
Maybe @Sebastianv650 can review this

Marlin/language_de.h

 #define MSG_RETRACT                         _UxGT("Retract")
 #define MSG_MOVE_AXIS                       _UxGT("Bewegen")
 #define MSG_LEVEL_BED                       _UxGT("Bett nivellieren")
+#define MSG_MOVING                          _UxGT("In Bewegung...")
+#define MSG_FREE_XY                         _UxGT("Abstand XY")
 #define MSG_MOVE_X                          _UxGT("X")
 #define MSG_MOVE_Y                          _UxGT("Y")
 #define MSG_MOVE_Z                          _UxGT("Z")
 #define MSG_FILAMENT                        _UxGT("Filament")
 #define MSG_VOLUMETRIC_ENABLED              _UxGT("E in mm³")
 #define MSG_FILAMENT_DIAM                   _UxGT("D Fil.")
+#define MSG_ADVANCE_K                       _UxGT("Advance Faktor")
 #define MSG_CONTRAST                        _UxGT("LCD Kontrast")
 #define MSG_STORE_EEPROM                    _UxGT("EPROM speichern")
 #define MSG_LOAD_EEPROM                     _UxGT("EPROM laden")
 #define MSG_CONTROL_RETRACT_RECOVER         _UxGT("UnRet mm")
 #define MSG_CONTROL_RETRACT_RECOVER_SWAP    _UxGT("Wechs. UnRet mm")
 #define MSG_CONTROL_RETRACT_RECOVERF        _UxGT("UnRet  V")
-#define MSG_AUTORETRACT                     _UxGT("AutoRetract")
+#define MSG_AUTORETRACT                     _UxGT("Autom. Retract")
 #define MSG_FILAMENTCHANGE                  _UxGT("Filament wechseln")
 #define MSG_INIT_SDCARD                     _UxGT("SD-Karte erkennen")  // Manually initialize the SD-card via user interface
 #define MSG_CNG_SDCARD                      _UxGT("SD-Karte getauscht") // SD-card changed by user. For machines with no autocarddetect. Both send "M21"
 #define MSG_DELTA_CALIBRATE_Y               _UxGT("Kalibriere Y")
 #define MSG_DELTA_CALIBRATE_Z               _UxGT("Kalibriere Z")
 #define MSG_DELTA_CALIBRATE_CENTER          _UxGT("Kalibriere Mitte")
+#define MSG_DELTA_AUTO_CALIBRATE            _UxGT("Autom. Kalibrierung")
+#define MSG_DELTA_HEIGHT_CALIBRATE          _UxGT("Delta Höhe setzen")
 #define MSG_DEBUG_MENU                      _UxGT("Debug Menu")
 #define MSG_PROGRESS_BAR_TEST               _UxGT("Fortschrittb. Test")