drag and drop of input also for mobile

Currently reordering the input is possible via click (to select the start input) and another click (to move it to the destination). This is a bit unusual but easier to use especially for many locations. Still it might prevent users from getting familiar.

See #224 where it was implemented on Desktop.

@easbar suggested that instead of a normal drag&drop it would be nice to be able to "swipe to the right" and only now some additional icons appear so that the inputs can be dragged. Or via long press or similar. For mobile drag&drop we probably need a library as suggested in #224.