feat: report the virtual IPs vip-manager and keepalived declare

LinuxDriver mixes in napalm-device-types' VirtualIpsMixin (4.2.0) and
carries its command on the exec channel: with the awk filter it is about
4 kB, past the line the PTY netmiko holds reliably takes. Root first,
then without it (NetOrk/netork#829).

Version 0.4.0.

napalm_linux/linux.py

@@ -44,6 +44,7 @@ from napalm_device_types import (
     OSDriver,
     SystemdServicesMixin,
     SystemdUnavailable,
+    VirtualIpsMixin,
     parse_apt_upgradable,
     open_stream_on_transport,
     parse_dnf_security,
@@ -206,6 +207,7 @@ def _arm_vendor_from_model(model: str) -> str:
 class LinuxDriver(
     KernelFactsMixin,
     ListeningSocketsMixin,
+    VirtualIpsMixin,
     SystemdServicesMixin,
     HostStatusMixin,
     ContainerEngineMixin,
@@ -1022,6 +1024,15 @@ class LinuxDriver(
             return self._run_privileged(command, 60)
         return self._send(command, read_timeout=60)
 
+    def _run_virtual_ips_command(self, command: str, *, privileged: bool) -> str:
+        """The transport for ``VirtualIpsMixin.get_virtual_ips``: an exec channel.
+
+        The command carries its awk program and is about 4 kB, past the line the
+        PTY netmiko holds reliably takes. Read-only either way; root only because
+        the configuration may be root's alone.
+        """
+        return self.run_command(command, privileged=privileged, timeout=60).stdout
+
     # ------------------------------------------------------------------
     # OSDriver – package management
     # ------------------------------------------------------------------