Add VictoriaMetrics to remote storage integrations (#1210)

* Add VictoriaMetrics to remote storage integrations

Mention that VictoriaMetrics supports direct PromQL querying.
Signed-off-by: Aliaksandr Valialkin <valyala@gmail.com>

* Removed the confusing part about remote read support for VictoriaMetrics

VictoriaMetrics doesn't support remote read API, so remove that part
Signed-off-by: Aliaksandr Valialkin <valyala@gmail.com>

content/docs/operating/integrations.md

@@ -47,6 +47,7 @@ data volumes.
   * [OpenTSDB](https://github.com/prometheus/prometheus/tree/master/documentation/examples/remote_storage/remote_storage_adapter): write
   * [PostgreSQL/TimescaleDB](https://github.com/timescale/prometheus-postgresql-adapter): read and write
   * [SignalFx](https://github.com/signalfx/metricproxy#prometheus): write
+  * [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics): write
 
 ## Alertmanager Webhook Receiver