Change arguments format in endpoints

[artas728]

Update arguments format in endpoints

from:

@app.listen("some.publish.subject")
async def receive_messages(subject, message):
    print(f"got message {message}")

to

@app.listen("some.publish.subject")
async def receive_messages(msg):
    print(f"got message {msg.parsed_data}")

where msg is an object that keeps many parameters:

msg.subject
msg.data                    #raw data
msg.parsed_data       #handled data
msg.header
msg.any_another_parameter