Fix JSON output when using -j or --json option

[htrgouvea]

Context:

The Nozaki tool includes a -j or --json option that formats the output as a JSON object. However, the current implementation does not produce valid JSON when there is more than one item in the response. This issue needs to be addressed to ensure compliance with the JSON standard.

What is needed to do:

Update the implementation of the -j/--json option to produce valid JSON when multiple items are returned. For example, wrap multiple results in an array to ensure the output is valid JSON.
Add automated tests to verify the JSON output for single and multiple items.
Update the documentation to clarify that the output will always be valid JSON.

Definition of done:

The output of the -j or --json option is valid JSON, regardless of the number of items in the response.
Automated tests confirm the correctness of the JSON output.
Documentation is updated with examples of the JSON output.