metrics: make metrics endpoint toggleable

docs/examples/kustomize/base/configmap.yaml

@@ -5,5 +5,6 @@ metadata:
 data:
   server_url: $(PUBLIC_PROTO)://$(PUBLIC_HOSTNAME)
   listen_addr: "0.0.0.0:8080"
+  metrics_enabled: "true"
   metrics_listen_addr: "127.0.0.1:9915"
   ephemeral_node_inactivity_timeout: "30m"

docs/examples/kustomize/postgres/deployment.yaml

@@ -30,6 +30,11 @@ spec:
                 configMapKeyRef:
                   name: headscale-config
                   key: metrics_listen_addr
+            - name: METRICS_ENABLED
+              valueFrom:
+                configMapKeyRef:
+                  name: headscale-config
+                  key: metrics_enabled
             - name: DERP_MAP_PATH
               value: /vol/config/derp.yaml
             - name: EPHEMERAL_NODE_INACTIVITY_TIMEOUT

docs/examples/kustomize/sqlite/statefulset.yaml

@@ -31,6 +31,11 @@ spec:
                 configMapKeyRef:
                   name: headscale-config
                   key: metrics_listen_addr
+            - name: METRICS_ENABLED
+              valueFrom:
+                configMapKeyRef:
+                  name: headscale-config
+                  key: metrics_enabled
             - name: DERP_MAP_PATH
               value: /vol/config/derp.yaml
             - name: EPHEMERAL_NODE_INACTIVITY_TIMEOUT