Fix gluetun DNS: disable DoT, use k8s coredns as plaintext resolver

DoT (port 853) to 1.1.1.1 through ProtonVPN VPN tunnel gets TCP RST,
causing gluetun healthcheck to fail (can't resolve github.com /
cloudflare.com). k8s coredns at 10.43.0.10 is reachable via eth0
within FIREWALL_OUTBOUND_SUBNETS, bypassing the VPN for DNS while
letting all other traffic tunnel correctly.

Also rename VPN_ENDPOINT_IP/PORT to WIREGUARD_ENDPOINT_IP/PORT to
suppress gluetun deprecation warnings.

servers/legion/k8s/fornax/worker/base/deployment.yaml

@@ -75,12 +75,14 @@ spec:
               value: PLACEHOLDER_PUBLIC_KEY
             - name: WIREGUARD_ADDRESSES
               value: 10.2.0.2/32
-            - name: VPN_ENDPOINT_IP
+            - name: WIREGUARD_ENDPOINT_IP
               value: PLACEHOLDER_ENDPOINT_IP
-            - name: VPN_ENDPOINT_PORT
+            - name: WIREGUARD_ENDPOINT_PORT
               value: "51820"
-            - name: DNS_KEEP_NAMESERVER
-              value: "on"
+            - name: DOT
+              value: "off"
+            - name: DNS_ADDRESS
+              value: "10.43.0.10"
             - name: FIREWALL_OUTBOUND_SUBNETS
               value: 10.42.0.0/16,10.43.0.0/16
           ports: