Multiple Ways to Register Your Dependencies with ASP.NET Core 3

With the new previews of dotnetcore there are new project templates but also a more generic hosting system, instead of having a Web specific host builder or Worker/services host builder there is a new "generic" host which they are all based on. These are all brought together under IHost. With this and other patterns/practices there are now multiple ways of registering your services. Let's take a look.