Alternative URLs

[UlisesGascon]

As proposed by @rajbos in #44 (comment), it will be nice to include custom urls with an argument like custom-api-url=https://myalternativeapi.com.

Do we need to map the org and repo to the new url? I mean.. currently we use https://api.securityscorecards.dev/projects/github.com/nodejs/node but this can be replaced by https://myalternativeapi.com/projects/github.com/nodejs/node, but we might need something more flexible than replace the domain like https://myapi.com/v1/security/{org}/reporting/{repo}/scorecard