[bug] When there are multiple subscriptions matching AEDES should respond with the highest sub QoS

> MQTT-3.3.5-1: The Server MUST deliver the message to the Client respecting the maximum QoS of all the matching subscriptions. In addition, the Server MAY deliver further copies of the message, one for each additional matching subscription and respecting the subscriptions QoS in each case.

See lib/client.js deliverQoS function