Rename [Nn]amespace -> [Uu]ser in go code

Use gopls, ag and perl to rename all occurances of Namespace

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

metrics.go

@@ -8,34 +8,34 @@ import (
 const prometheusNamespace = "headscale"
 
 var (
-	// This is a high cardinality metric (namespace x machines), we might want to make this
+	// This is a high cardinality metric (user x machines), we might want to make this
 	// configurable/opt-in in the future.
 	lastStateUpdate = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Namespace: prometheusNamespace,
 		Name:      "last_update_seconds",
 		Help:      "Time stamp in unix time when a machine or headscale was updated",
-	}, []string{"namespace", "machine"})
+	}, []string{"user", "machine"})
 
 	machineRegistrations = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: prometheusNamespace,
 		Name:      "machine_registrations_total",
 		Help:      "The total amount of registered machine attempts",
-	}, []string{"action", "auth", "status", "namespace"})
+	}, []string{"action", "auth", "status", "user"})
 
 	updateRequestsFromNode = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: prometheusNamespace,
 		Name:      "update_request_from_node_total",
 		Help:      "The number of updates requested by a node/update function",
-	}, []string{"namespace", "machine", "state"})
+	}, []string{"user", "machine", "state"})
 	updateRequestsSentToNode = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: prometheusNamespace,
 		Name:      "update_request_sent_to_node_total",
 		Help:      "The number of calls/messages issued on a specific nodes update channel",
-	}, []string{"namespace", "machine", "status"})
+	}, []string{"user", "machine", "status"})
 	// TODO(kradalby): This is very debugging, we might want to remove it.
 	updateRequestsReceivedOnChannel = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: prometheusNamespace,
 		Name:      "update_request_received_on_channel_total",
 		Help:      "The number of update requests received on an update channel",
-	}, []string{"namespace", "machine"})
+	}, []string{"user", "machine"})
 )