Get JSON tables from Mathics-Scanner rather than regenerate them in mathics-code

[rocky]

Both mathics-scanner and mathics-core need to read in JSON tables. We don't have to generate them twice. Instead, we can pick them up once from wherever Mathics-Scanner stores them.

CI tests would also get simplified.

(A partial explanation of how we got here. Initially, the scanner did not use the YAML/JSON information, or used it only sparingly. Over time, that's been changing and will change even more in the future. In mathics-scanner, we've encapsulated reading the JSON files, so I think it is just a matter of calling functions that already exist in Mathics-Scanner.)