Remove connectors API docs (#1607)

We've fully removed Cloud Import as a feature, which has been deprecated for nearly two years at this point. Now that there are no customers on it (and the code no longer exists), let's remove all references to it from our docs.

Author: chris-bonadonna-mixpanel

openapi/openapi.config.yaml

@@ -1,6 +1,5 @@
 apiDefinitions:
   annotations: ./src/annotations.openapi.yaml
-  connectors: ./src/connectors.openapi.yaml
   data-pipelines: ./src/data-pipelines.openapi.yaml
   export: ./src/export.openapi.yaml
   gdpr: ./src/gdpr.openapi.yaml