INTEXT-111 fixing problems with using property placeholder and SpEL expressions in consumer context 'group-id' and producer context 'topic'

Yes and yes, we shouldn't register these things as beans, I just found that this causes another issue, when you have more than one consumer context defined + more then one input channel adapter, mainly because these beans being registered, and following code in KafkaConsumerContext:
```java
	public void setBeanFactory(final BeanFactory beanFactory) throws BeansException {
		consumerConfigurations = (Map<String, ConsumerConfiguration<K,V>>)
				(Object) ((ListableBeanFactory) beanFactory).getBeansOfType(ConsumerConfiguration.class);
	}
```

Once you have more than consumer context and input channel adapter, you end up with following exception:
> java.lang.IllegalStateException: Iterator is in failed state

Should I open separate issue to handle this case? I have some ideas how to fix it.