Not used since console support was dropped. Drop it to simplify
migration of the net.box state machine to C.

@TarantoolBot document
Title: Update the net.box state machine diagram

New diagram from the net.box source code:

```
initial -> auth -> fetch_schema <-> active

(any state, on error) -> error_reconnect -> auth -> ...
                                         \
                                          -> error
(any state, but 'error') -> closed
```