Added fluent api for microsoft-esque dependency registration

[tofi92]

Hi, I added a small fluent API for the default Microsoft DI container. This should be familiar to any C# developer using the default DI container.

It is 100% backwards compatible, so manual registration still works - this is reflected in the README.

[f1ana]

Interesting idea! This could make registration a more intuitive.
My only concern is that if a dev wants to use a Scoped lifetime, they would be unable to do so, since this code assumes Transient all the way down.

[tofi92]

As HttpClient is also a transient dependency, I think there is no benefit for the services to be scoped, because the most costly resource, the HttpClient, will be created everytime regardless.

[f1ana]

As HttpClient is also a transient dependency, I think there is no benefit for the services to be scoped, because the most costly resource, the HttpClient, will be created everytime regardless.

The IHttpClientFactory, which generates the HttpClients, is a singleton correct?
Using this source for reference: https://github.com/dotnet/runtime/blob/main/src/libraries/Microsoft.Extensions.Http/src/DependencyInjection/HttpClientFactoryServiceCollectionExtensions.cs#L41

[tofi92]

Ahh I misremembered and thought HttpClient was used :) Anyway I think it won't make a difference.

[f1ana]

Still interested in this PR, however I do not want to force a developer consuming this library to use a prescribed lifetime.