Feature Proposal: Add Config API support for custom OSS and Self-Managed deployments

Certain features require the legacy Config API. Presently we auto-detect Cloud API root and from that we auto-associate Cloud's Config API endpoint. To reach parity, we would need to add more advanced logic to calculate a Config API root for self-deployed instances as well.

https://github.com/airbytehq/PyAirbyte/blob/db63acadba3bd82f8a1c94ebda7b107c93fdb3b7/airbyte/_util/api_util.py#L68-L74