`--output json` to provide ONLY json

[QuAzI]

Would be nice to have a way to get only clean responses without framing and extra data at least for json

---------------------

=== Configuration ===

{
  "payload"
}

1 requests processed (1 succeeded)

there I need only

{
  "payload"
}

to process with jq/fx

[QuAzI]

Just forgot about #879