Read spring header annotation

[timonback]

This uses #579 as a starting point and relates to #563

With this change:

• Springwolf is able to parse spring @Header annotations for spring method and class listeners like @KafkaListener (@Headers cannot be parsed, as it is a map that is populated during runtime method invocation)
• The Kafka Key is mapped into the message binding (additionally), the key is kept in the header as well, which is demonstrated in the example
• The ComponentsService becomes a pure stateful services that only stores swagger schema data. The converting of class to a swagger schema is moved to the new SwaggerSchemaService (refactor)
• The AsyncHeader signature gets an additional parameter headerSchema to pass the info for Kafka. I am not 100% sure about this change, but it seems easiest at this point.

CC: @ctasada

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