feat(connectors): Implement MQTT source & sink

[Luishfs]

Description

In order to get iggy connectors on a broader range of devices, i'm proposing to implement the MQTT protocol for both sources & sinks.

Affected area / component

Connectors

Proposed solution

I've did some research on Rust crates for the MQTT protocol, and the most reliable ( along with continuous maintenance ) seems to be flowsdk. I've made a sink MVP with the sink target being a rabbitmq MQTT endpoint (with mqtt 5) and it works as expected:

So the idea would be:

• Implement both Sink and Source with MQTT 5
• Allow for MQTT 3 after MQTT 5 is valid ( the sdk allow for both )

Alternatives considered

No response

Contribution

• I'm willing to submit a pull request to implement this feature

Good first issue

• I think this could be a good first issue for a new contributor

[Luishfs]

@hubcio please assign me

[hubcio]

@Luishfs assigned