Adding kafka output support

[P1llus]

Tested this with a local Kafka instance:

Start Kafka:
docker run -p 9092:9092 -d bashj79/kafka-kraft

Send data:

> ./stream log --addr 127.0.0.1:9092 -p kafka --kafka-topic test ./foo.txt
{"level":"debug","ts":"2022-03-22T15:23:29.439+0100","caller":"output/util.go:28","msg":"Connecting...","address":"127.0.0.1:9092"}
{"level":"info","ts":"2022-03-22T15:23:29.483+0100","caller":"output/util.go:41","msg":"Connected","address":"127.0.0.1:9092"}
{"level":"debug","ts":"2022-03-22T15:23:29.483+0100","caller":"command/log.go:81","msg":"Sending log line.","address":"127.0.0.1:9092","log":"./foo.txt","line_number":1}
{"level":"info","ts":"2022-03-22T15:23:29.525+0100","caller":"command/log.go:94","msg":"Log data sent.","address":"127.0.0.1:9092","log":"./foo.txt","total_bytes":19,"total_lines":1}

Double check that data is actually stored in topic:

bash-5.1# /opt/kafka/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning --max-messages 10
testmessage hey hey

While I could add in more options, currently it supports only Topic. We don't need things like groups etc, as we are not consuming but simply creating the topic and its data.

If you would like me to add more debugging output or similar, just let me know, but I feel that for stream this should be sufficient.

[elasticmachine]

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• Start Time: 2022-03-23T16:45:39.000+0000

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[P1llus]

Adding some tests as well now

[andrewkroh]

Please wait for the GH actions to run. Currently there are no checks on the last commit and I assume it's because of issues with GH infrastructure.

[andrewkroh]

Please add a changelog entry.