Uno Platform support
## 🚀 Feature Requests

Add support for Uno Platform

### Contextualize the feature

Take MvvmCross to Uno WASM!

### Describe the feature
<!--- Use as much detail as possible here! --->

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