Feature/scroll page dots

[Vpdwivedi]

• Option to show/hide page dots
• Option to show/hide survey title
• Added Scroll for Page dots for handling more pages (dots)

[goxiaoy]

This PR is unnecessary. You can customize by using SurveyConfiguration and builder

s.SurveyConfiguration(
  titleBuilder: (BuildContext context, s.Elementbase element, Widget child)=>child,
  ...
  child: s.SurveyWidget(
    survey: s.surveyFromJson(survey),
    builder: (context)=>SurveyLayout( stepperBuilder : (BuildContext context, int pageCount, int currentPage)=>YourStepperBuilder),
    onChange: (v) {
      print(v);
    },
    onSubmit: (v) {
      print(v);
    },
  )
)

[goxiaoy]

It's not recommend to use DotStepper when there are too many pages, you may use style like https://pub.dev/packages/flutter_web_pagination