Change run_starlark_code to take additional arguments

[dcollien]

This changes run_starlark_code to take in additional arguments:

const result = run_starlark_code(codeString, "functionName", more, arguments, here, to, pass, to, the, function);

It's backwards compatible with the original run_starlark_code which only takes a single argument. If given a single argument (just the code), it still runs the main function with no arguments.

It also converts any JSON-like arguments to starlark equivalents.

The second commit adds support for returnValue

console.log(result.returnValue);