Support for .NET 8 as a stepping stone towards containers #4161
Description
As a stepping stone towards containers, ServiceControl instances have been migrated to .NET 8, making them self-contained and eliminating the need for a specific .NET version on the operating system. This upgrade, which includes a shift to ASP.NET Core, System.Text.Json and the introduction of NServiceBus v9, modernizes the code base and overall enables taking advantage of the latest .NET 8 features and performance improvements.