MQTT Connector or Delivery Type

## Feature Request We would like to automate forwarding iot-data to our customers, which sometimes want to recieve those informations via webhook or via mqtt. ### Motivation We currently have 2 systems publishing data to webhook as batches and to distinct eclipse mqtt server seperatly, managing customers credentials for this server as well. ### Proposal We would like to suggest to eigher integrate the eclipse-mosquitto mqtt server and allowing application owners to map data into their own topics like v1/applicationId/d/topicNameBasedOnWebhookDateOrStatic. AND/OR define publishing data to publish the data to an external mqtt server. ### Alternatives like our currently duplicated aproach ### Disclaimer We dont know 100%, how streams are working currently, maybe thats similar or has overlaps. We would understand, if thats not the target of Svix, but we considdered it worth mentioning as, it could be a huge new USP :) And would reduce maintenance on our part :) Thanks yall :)