[BUG] Default oas file generated has a different name than the default name expected in oas-tools/core

[josemgarcia]

When generating a server with the CLI, the default configuration included in index.js does not specify the OAS file the server was generated from.

The validation that oas-tools perform expects that, if no oas file is specificied in the configuration object passed to the initialize function, the default OAS file will be at api/oas-file.yaml. However, the CLI generates it as api/oas-doc.yaml, causing an initialization error as a consequence if no explicit config is provided.

It would be better to sync somehow the two default names both in CLI and in core modules.