Updating NumberPicker, TimePicker, DatePicker to fit different screen and font sizes.

1. Now the NumberPicker has minWidth/minHeight that is the lower bound
   of the correspodning size for which the widget looks well enough to
   be usable. There is also maxWidth/masHeight that is the upper bound
   of the corresponding size for which the widget looks best. The picker
   tries to greedily reach the max dimesions for which it looks best.

2. The NumberPicker was not taking care of the max width of the items
   is shows numbers/strings mapped to numbers. Now if not explicitly
   specified the widget computes the maxWidth at which it looks best
   based on the content it shows.

3. Removed an unnecessary layout for number picker on tablets.

4. Updated the TimePicker/DatePicker to not hard-code width for the
   number pickers it uses, rahter wrap the content.

bug:5417100

Change-Id: I432aa96185961e59a058a2565b15265ba7394818