Converts the Microsoft.iOS.Windows.Sdk NuGet package into a proper
[workload SDK pack][0]. The entry point for this pack has been changed,
and it is now imported through the `WorkloadManifest.targets` file
included in `Microsoft.NET.Workload.iOS`, rather than being imported
directly from `Microsoft.iOS.Sdk`.
Import ordering has otherwise changed slightly. The following files are
now imported before the majority of the `Microsoft.iOS.Sdk` (and the
majority of the .NET SDK targets):
* Xamarin.iOS.Common.Before.props
* Xamarin.iOS.Common.Before.targets
After this the majority of the .NET SDK targets will load, followed by
the `Microsoft.iOS.Sdk` targets. Finally, everything declared in the
`<AfterMicrosoftNETSdkTargets/>` hook loads, which consists of:
* Microsoft.iOS.Windows.Sdk.targets
* tools/msbuild/*
[0]: https://github.com/dotnet/designs/blob/main/accepted/2020/workloads/workload-manifest.md#sdk-packs
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>
b88c3bb031