feat: harden the host's SSH server through napalm-device-types

LinuxDriver mixes in OpenSshServerMixin, so netOrk can take algorithms
ssh-audit flagged out of what sshd offers. The work is the base's; the
driver brings run_command, which already runs as root over an exec channel.

Requires napalm-device-types 4.5.0; bumps to 0.5.0. NetOrk/netork#1027

napalm_linux/linux.py

@@ -41,6 +41,7 @@ from napalm_device_types import (
     HostStatusMixin,
     KernelFactsMixin,
     ListeningSocketsMixin,
+    OpenSshServerMixin,
     OSDriver,
     SystemdServicesMixin,
     SystemdUnavailable,
@@ -208,6 +209,7 @@ class LinuxDriver(
     KernelFactsMixin,
     ListeningSocketsMixin,
     VirtualIpsMixin,
+    OpenSshServerMixin,
     SystemdServicesMixin,
     HostStatusMixin,
     ContainerEngineMixin,