DateField styling improvements

The date field consists of four elements: date picker, hours and minutes field and a set-to-now button.

It is styled in such a way that all elements fit on one line when the side editor is at its smallest and even if the field is in a first level compound.

But if the field has a label that is long it will not fit very nicely above the date picker field. Making the editor bigger doesn't help because the width of the date picker input field is now fixed. It would be nice if it would take more space if it needs it.

In case the fields in some case do not fit on the same line, all fields after the date picker should move to the next line as a group.