StreamsExecutionEnvironment instances should be able to be registered as component

[fhussonnois]

Currenlty a StreamsExecutionEnvironment instance can be registed directly through the AzkarraContext#addExecutionEnvironment method and from the configuration.

The following example shows how to define an environment using configuration :

azkarra {
  // Create a environment for running the WordCountTopology
  environments = [
    {
      name: "dev"
      config = {}
      jobs = [
        {
          name = "word-count-demo"
          description = "Kafka Streams WordCount Demo"
          topology =  "WordCountTopology"
          config = {}
        }
      ]
    }
  ]
}

But, this is not possible to declare an environement as a component, i.e :

Example:

@Factory
public class EnvironmentFactory {

    @Component
    @Named("dev")
    public StreamsExecutionEnvironment devEnv() {
       return DefaultStreamsExecutionEnvironment.create();
    }
}

or

azkarraContext.registerSingleton("dev",  
   StreamsExecutionEnvironment.class, 
   () -> DefaultStreamsExecutionEnvironment.create()
); 

This issue is an improvement to update the DefaultAzkarraContext and more specifically the private method preStart to automatically register all components of type StreamsExecutionEnvironment on context startup.