RSTB-41 disable DHCP server

In bluerobotics#2988 BlueOS defaultet to
running a DHCP server. This will not work for our needs, as we handle
our own DHCP server, and we've seen instance of this DHCP server taking
over client, unfortunately.

Author: goasChris

core/services/cable_guy/main.py

@@ -43,7 +43,7 @@
         NetworkInterface(
             name="eth0",
             addresses=[
-                InterfaceAddress(ip="192.168.2.2", mode=AddressMode.Server),
+                InterfaceAddress(ip="192.168.2.2", mode=AddressMode.Unmanaged),  # Disable DHCP server
                 InterfaceAddress(ip="0.0.0.0", mode=AddressMode.Client),
             ],
         ),