🚀 Feature Request: Add access to Entry Cursor Position

## 🚀 Feature Requests

Add access to Entry Cursor Position. For my Purpose it's to Select Text on Focus doing [this](https://stackoverflow.com/questions/28194231/automatically-select-all-text-on-focus-xamarin)

### Contextualize the feature
This heavily speeds up user input, they can decide to overwrite the current select or simply hit tab/next and go to the next element

### Describe the feature
set Entry Cursor Position as a public property

### Platforms affected (mark all that apply)
- [X] :iphone: iOS
- [X] :robot: Android
- [X] :checkered_flag: WPF
- [X] :earth_americas: UWP
- [X] :apple: MacOS
- [X] :tv: tvOS
- [X] :monkey: Xamarin.Forms