support @Produces in partial-beans

it allows to use partial-bean methods also as simple producers of (qualified) types. the main use-case is about exposing injectable values without additional producer-classes since partial-beans are mainly about exposing values (and invoking generic-methods) easily. implication: we don't need to support disposer-methods for now.

example:

@TypeSafeConfig //partial-bean binding
public interface Config
{
    @Produces
    @ApplicationName //custom
    String name();

    String version();
}
//+ handler

that allows to inject Config and access the methods or just inject a string qualified with @ApplicationName. -> it's mainly a shortcut similar to producers based on BaseConfigPropertyProducer.

a version based on BaseConfigPropertyProducer would look like:

public class ConfigProducer extends BaseConfigPropertyProducer
{
    @Produces
    @ApplicationName
    public String applicationName(InjectionPoint injectionPoint)
    {
        return getStringPropertyValue(injectionPoint);
    }
}