Feature Request: Add CLI to finalize packet by key

[VictorTrustyDev]

On explorer, packet key will display as hex encoded like this 00012f65766d5f31303030322d312f00000000000002202f4f4e5f524543562f6368616e6e656c2d302f000000000000000b

so it would be nice to have a CLI to finalize by packet key.

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Note: currently I see the packet-key string is being computed like this string([]bytes), it Not read/copy-able.
So this format will need to decode hex into buffer and do string() before set into msg to make it work.