DOC: configuration: fix broker description
DOC: configuration: fix broker description

the parameter `broker` is deprecated
enhance description of source/destination_pipeline_broker:
- use link syntax
- add amqp
- add note on usefulness

certtools/intelmq,certtools/intelmq,certtools/intelmq,aaronkaplan/intelmq,aaronkaplan/intelmq,aaronkaplan/intelmq