Add the list of user defined parameters to the Json report summary

[jcpitre]

Describe the problem

In https://github.com/MobilityData/gtfs-validator/issues/1503 there was a request that we put user defined parameters (cli arguments) in the summary of the json report. This is still to be done. Note however that some user defined parameters are already present in the summary, e.g.

 "gtfsInput": "file:///Users/jcpitre/datasets/test.zip",
 "threads": 1,
 "outputDirectory": "qaz"

although not in a separate section of the summary.

Proposed solution

Add a section about user defined parameters (cli arguments) in the json report summary OR decide that we don't need because we have enough of this information already in the report. Consider how to add this to the UI.

Alternatives you've considered

No response

Additional context

No response