Make documentation standalone and generalize examples

docs/reference/configuration.md

@@ -105,8 +105,8 @@ comma separated. Empty, the default, is the minimal engine.
 | `server` | all of the above |
 
 A node whose extra is missing says so on the canvas. The same names work as
-pip extras, such as `pip install 'fluksio[mqtt]'`. Connector packages built
-with `make connectors` are installed into the image too.
+pip extras, such as `pip install 'fluksio[mqtt]'`. To include connectors, place
+their wheels in `backend/connector-wheels/` before building the image.
 
 ## Environment