postinst: Add iproute and set up DNS

Without these the VMs are almost unusable.

alpine_postinst

@@ -9,9 +9,13 @@ echo "$ssh_key" >> /root/.ssh/authorized_keys
 
 # Install bird and maybe other tools
 apk update
-apk add bird
+apk add bird iproute2
 rc-update add bird default
 
+# DNS setup
+echo "nameserver 1.1.1.1" > /etc/resolv.conf
+echo "nameserver 2620:fe::fe" >> /etc/resolv.conf
+
 # Run nameif at boot to set network names
 # Doc: https://wiki.alpinelinux.org/wiki/Custom_network_interface_names
 # NOTE: This does not seem to work.