refactor!: drop the _docker_bin override

napalm-linux 0.3.0 drops the Docker CLI methods the override served.
_container_engine_binary("docker") returns Container Station's path
itself, which is all netOrk needs: it reaches the engine through
open_container_engine (NetOrk/netork#765, phase 9).

Requires napalm-linux >= 0.3.0. Version 0.3.0.

README.md

@@ -32,7 +32,7 @@ output is how a driver ends up passing its own tests and failing on a real NAS.
 | `start_vm`, `stop_vm`, `reboot_vm` | `virsh` | pending harvest |
 | `set_service_enabled` | `setcfg`, `/etc/init.d` | pending harvest |
 | `get_device_warnings` | derived from the above | pending harvest |
-| `get_docker_info` | inherited, via `_docker_bin()` | ✅ |
+| `container_engines`, `open_container_engine` | Container Station's docker, `system dial-stdio` | ✅ |
 | `get_services`, `get_users`, `get_processes` | inherited from `LinuxDriver` | ✅ |
 | `get_health_metrics` | inherited (UCD-MIB over SNMP) | ✅ |
 | `ping`, `ping_sweep` | inherited from `LinuxDriver` | ✅ |
@@ -94,9 +94,10 @@ QNAP running Virtualization Station is a NAS *and* a hypervisor, and
 ### Docker
 
 Container Station does not put `docker` on `PATH`; it lives under
-`/share/<pool>/.qpkg/container-station/`. The Docker *logic* stays in
-`LinuxDriver` and only the path is overridden here, via the `_docker_bin()`
-hook.
+`/share/<pool>/.qpkg/container-station/`. This driver only says where:
+`_container_engine_binary("docker")` returns the path it found, and
+`open_container_engine("docker")` from napalm-device-types reaches the Engine
+API through it. What runs on the engine is netOrk's (NetOrk/netork#765).
 
 ## Harvesting fixtures