* Add .NET 8 target to packable projects
* Update test projects
* Update sample projects to target .NET 8
* Update main Avalonia package to target .NET 8 as well
* Remove MSBuildEnableWorkloadResolver hack and some minor change
* Use net8.0 in nuke build as well
* Pin 8.0.0 SDK
* Adjust API validation
* Pin a valid version
* Remove net461 target from Avalonia package
* Remove unused net6.0 target from Avalonia.Designer.HostApp
* Adjust API diff
* Update ControlCatalog.Android.csproj
* Remove MSBuildEnableWorkloadResolver
* Fix Browser issues on .NET 8
* Fix .NET 8 error
* Fix merge conflicts
* Replace explicit TFMs in .csproj files with a centralized registry
* Fix merge conflict
* Fix AvsLegacyWindowsTargetFrameworks and add hacks for the tests
* Update XCode project CommandLineArgument
---------
Co-authored-by: Nikita Tsukanov <keks9n@gmail.com>
Julien Lebosquain