Added date range selection capability

[Tarekka]

Users can now enable range selection on the calendar, which allows them to select a range of days instead of one day only, by selecting a start date followed by an end date. All days in between (and including) those days will be marked selected. This can be useful for booking applications where users are required to select a start and end day, without needing to open two separate calendars for each day.

To enable, set RangeSelectionEnabled to True in your calendar control, and optionally, set the RangeSelectionStartDate and RangeSelectionEndDate properties.

[antonioseric]

@Tarekka thank you for your PR we ware fixing bug around your feature. Soon it will be version with range selection dates.