Add keyed service registration support

[A-Ebrahimzadeh-dev]

Summary

This PR adds support for registering services with a service key in Scrutor.
Currently, Scrutor does not provide a way to register keyed services.
With this change, developers can specify a key when registering a service via ServiceDescriptorAttribute.

Changes

• Modified ServiceDescriptorAttribute to allow an optional ServiceKey property.
• Updated registration logic to respect ServiceKey if provided.
• Preserved backward compatibility for existing code without keys.

Motivation

Adding keyed services allows more flexible dependency injection scenarios,
such as having multiple implementations of the same interface and selecting them by key at resolution time.

Example

[ServiceDescriptor(serviceType: typeof(IMyService), lifetime: ServiceLifetime.Transient, serviceKey: "specificService")]
public class MyService : IMyService { }

[khellang]

Hi @A-Ebrahimzadeh-dev! 👋🏻

This looks like a good contribution, thank you! 🙏🏻

Would you be able to add some tests?

[A-Ebrahimzadeh-dev]

Hi @A-Ebrahimzadeh-dev! 👋🏻

This looks like a good contribution, thank you! 🙏🏻

Would you be able to add some tests?

Hi 👋🏻 Thanks a lot for the feedback! I’ve added the tests as requested. Please let me know if you’d like me to improve or adjust anything 🙏