feat(consume): add output flag to consume for full json output

[shousper]

I wanted this, so I wrote it.

• Deprecate --raw flag of consume subcommand.
• Add --output flag to consume subcommand with support for default (the current default tabwriter based output format), raw (the current --raw impl.) and a new json format.
• New json output format is meant to output all metadata + payload and key in a JSON payload for easier use with jq.
• Maintained automatic decoding and embedding of JSON format keys and payloads, similar to tabwriter output.

[birdayz]

sorry for the late response. this is great, thank you for the contribution!

[shousper]

@birdayz No worries. Thank you for this great tool! 🖖