Adding connection-info kcat support in aiven-client

[ftisiot]

About this change: What it does, why it matters

Kafkacat is the old name of the tool now named kcat, the PR adds the functions to retrieve the kcat call, we'll be then able to deprecate the kafkacat one and remove it safely some time in the future

[rominf]

Converted to draft since tests do not pass to prevent accidental merge.

[ftisiot]

Hi! In order to test this please find a Aiven for Kafka service and execute

avn service connection-info kcat  [SERVICE_NAME]

The output should be similar to

kcat -b HOST:PORT -X security.protocol=SSL -X ssl.ca.location=ca.pem -X ssl.key.location=service.key -X ssl.certificate.location=service.crt

If the Aiven for Apache Kafka uses SASL authentication you can use the -a sasl flag and you should get something like

kcat -b HOST:PORT -X security.protocol=SASL_SSL -X ssl.ca.location=ca.pem -X sasl.mechanisms=SCRAM-SHA-256 -X sasl.username=avnadmin -X sasl.password=PASSWORD

[HelenMel]

Good PR. I have one minor comment

[ftisiot]

@HelenMel could you please double check that everything is ok from your side?