fix: change payload 'any' type to 'schema' to match specification.

[VisualBean]

Message Payload is denoted in the specification as the Json Schema 'Any' type.
However, according to documentation and chat ive had with the asyncapi creator, we can expect it to be the Schema type instead, this also fixies "missing" documented cases of Referenced payloads, which is not a thing with 'any'.

• Changed Payload type from 'any' to 'schema'
• Fixed an issue with security references, as they were being written as the full reference, but rather should simply "reference" by name.
• Added a kafka streetlights test as well, to ensure we match.
• Added and refactored binding tests