Add `RequestLog.serviceName()`

RequestLog.name() was a great addition that provides a universal human-readable name of a request. However, it currently only reveals a method name. It would be nice if we also provide a similar API for getting the name of a service. For example:

Server.builder()
      .route()
          ...
          .defaultServiceName("MyService")
          .build(myService)
      .annotatedService()
          ...
          .defaultServiceName("MyService2")
          .build(myAnnotatedService)
      ...

If not specified, it could be auto-generated from the innermost class name, etc.

[ikhoon]

Had chat on methodName() and not all services has method name such as:

Server.builder()
      .service((ctx, req) -> {
          ...
          return HttpResponse.of(...);
      });

• RequestLog.serivceName() that returns an RPC service name or innermost class name for an annotated service.
• RequestLog.name() that returns only a method name or null if it is a plain Service.
• RequestLog.fullName() that returns a combined service and name. (ex: com.foo.bar.Service/method)

[ikhoon]

Do we need a new field in RequestLog or should we just prepend service name to name? I think a dedicated field is better for now.

I prefer having dedicated fields. My suggestions are:

• RequestLog.serivceName() that returns an RPC service name or innermost class name for an annotated service.
• RequestLog.methodName() that returns only a method name.
• RequestLog.name() that returns a combined service and method name. For example com.foo.bar.Service/method.