Add way to specify namespaces

Signed-off-by: Michel Hollands <michel.hollands@grafana.com>

charts/meta-monitoring/values.yaml

@@ -1,3 +1,8 @@
+namespacesToMonitor:
+- loki
+- mimir
+- tempo
+
 loki:
   loki:
     auth_enabled: false
@@ -27,31 +32,8 @@ loki:
 grafana-agent:
   agent:
     configMap:
+      create: false
+      name: "agent-configmap"
       key: 'config.river'
-      content: |
-        discovery.kubernetes "pods" {
-          role = "pod"
-          namespaces {
-            names = ["loki"] // make configurable
-          }
-        }
-        loki.source.kubernetes "pods" {
-          targets    = discovery.kubernetes.pods.targets
-          forward_to = [loki.write.local.receiver]
-        }
-        loki.write "local" {
-          endpoint {
-            url = "http://meta-loki.meta.svc.cluster.local:3100/loki/api/v1/push"  // set namespace via config
-          }
-        }
-        prometheus.scrape "pods" {
-          targets    = discovery.kubernetes.pods.targets
-          forward_to = [prometheus.remote_write.default.receiver]
-        }
-        prometheus.remote_write "default" {
-          endpoint {
-            url = "http://meta-mimir-nginx.meta.svc:80/api/v1/push"  // set namespace via config
-          }
-        }
 
 # mimir-distributed: