[Feature Request] Add MinimumDate and MaximumDate properties

[PenguinPero]

To decide if we want this..

And if we do want it, decide:

• How to actually implement it
• Gray-out not-selectable dates?
• Disable switching month/year before/later than min/max date?
• Colors, new bindable properties
• Test everything, some edge case scenarios

Reason: Some users might profit from this if they are using the Calendar as a custom DatePicker control

[PenguinPero]

@jsabic branch is already ready for this with implementation, needs review and test on iOS