[.NET] Add support for AOT-compiling into frameworks

[rolfbjarne]

As the title says.

Ref:

xamarin-macios/tests/common/DotNet.cs

Lines 129 to 130 in b111ce0

	} else if (components.Any (v => v.EndsWith (".appex", StringComparison.Ordinal))) {
	return false; // TODO

[rolfbjarne]

This will not be done in the .NET 6 time frame due to time constraints, so moving to .NET 7.

[rolfbjarne]

This will not be done in the .NET 7 time frame due to time constraints, so moving to .NET 8.

[rolfbjarne]

#17353 should probably be done first (it's simpler and faster to implement, and this issue would likely depend on that work anyways).

[rolfbjarne]

This will not be done in the .NET 8 time frame due to time constraints, so moving to .NET 9.