Show more lines in log queries in Grafana

The default maximum log lines shown in Grafana are 1000. This is
barely covering a few minutes in the httpd-logs.

The value of 10,000 can still be handled by the browser. More log
entries will cause the browser to cache as long as Grafana does not
provide pagination, which is planned for the future.

Change-Id: Ife84d161cd022300ff6f440920021e4176b770b9

charts/grafana/grafana.yaml

@@ -308,6 +308,8 @@ datasources:
       url: #@ "http://loki-{}.{}.svc.cluster.local:3100".format(data.values.namespace, data.values.namespace)
       access: proxy
       isDefault: false
+      jsonData:
+        maxLines: 10000
     - name: LokiPromQL
       type: prometheus
       url: #@ "http://loki-{}.{}.svc.cluster.local:3100/loki".format(data.values.namespace, data.values.namespace)