CodeReview and Refactoring for AutoCompleteView:
- fixes issues about suggestion;
- create AutoCompleteViewModel for the sample  (before it was in MainViewModel);
- rename the file AutoComplete for AutoCompleteView;
- in SelectedCommand it will give us or object and not an SelectedItemChangedEventArgs;
- organize the code;
- move TestPerson for the Model folder;
- delete the AutoCompleteSearchObject, should be used ToString()

Note: issue related with https://github.com/XLabs/Xamarin-Forms-Labs/issues/496