Add globbing support for WinUI

The WinUI team needs support for globbing support so that Visual Studio will not edit the .csproj whenever you add a .xaml file to the project. See this bug as a reference: https://github.com/microsoft/microsoft-ui-xaml/issues/2498

In following the same pattern as WPF, we can add a `UseWinUI` property that will pull in the `Microsoft.NET.WindowsDesktop.Sdk` and enable the globbing support.

If both `UseWinUI` and `UseWpf` are true, then the SDK can assume all xaml files are for WPF. The WinUI nuget will respect the use of `UseWpf` and not invoke the winui xaml compiler if that is the case. If only `UseWinUI` is true, then the SDK should not invoke PBT. Below is a table describing the different combinations and what should happen:

| UseWpf | UseWinUI | Xaml Compiler invoked |
| :-: | :-: | :-: |
| `True` | `True` | PBT |
| `True` | `False` | PBT |
| `False` | `True` | WinUI Compiler |
| `False` | `False` | neither |