your request is feasible. You can make a Java/Groovy program which will generate the ReadyAPI project from OpenAPI definition (e.g., in YAML format) and create a test case, starting with the authentication.
Though, the main strength of ReadyAPI, which is in my opinion the efficient user interface to create and manage tests.
Also, creating proper test data could be a challenge. Of course you can generate them from the examples from OpenAPI definition, but that would require well-designed APIs. Or, you can make your own test data generator.
I have done a similar thing (generating test projects) in the past in SoapUI, but used the test data from the prepared files, not generating them on the fly.
