Provide possibility to define alternative NUGET API base url

For users which use an alternative NuGet repository provider like JFROG Artifactory is necessary to define an alternative NUGET API url

cdxgen/utils.js

Line 4019 in d48411c

const NUGET_URL = "https://api.nuget.org/v3/registration3/";

[prabhu]

@hornpecom Could you explain a bit more? Is it enough to simply set the jfrog url here? What about authentication and returned json response since the code expect nuget specific response for version and license detection.

Good point. You are right, in some cases authentication is required. The tool cyclonedx-dotnet offers the functionality
See https://github.com/CycloneDX/cyclonedx-dotnet#options

-u|--url <BASE_URL>                                                    Alternative NuGet repository URL to https://<yoururl>/nuget/<yourrepository>/v3/index.json
-us|--baseUrlUsername <BASE_URL_USER_NAME>                             Alternative NuGet repository username
-usp|--baseUrlUserPassword <BASE_URL_USER_PASSWORD>                    Alternative NuGet repository username password/apikey

The response format must be the same as from the nuget.org. Would be my expectation

[prabhu]

@hornpecom Thank you. It might be time to add support for a configuration file where these parameters could be specified instead of adding more cli arguments to cdxgen. I will review this and reply with questions and help with testing.