deployment/alerts: rename alerts.yml to alerts-single-node.yml

The change should reduce confusion for users where `alerts.yml`
belongs to. Before, developers could mistakenly assume that
`alerts.yml` was related to both single and cluster installations.
In result, rule `MetadataCacheUtilizationIsTooHigh` was added only
to `alerts.yml` and not copied to `alerts-cluster.yml`.

The rename change should bring more context into the file name
and reduce confusion in the future.

Signed-off-by: hagen1778 <roman@victoriametrics.com>

deployment/docker/README.md

@@ -151,7 +151,7 @@ Some alerting rules thresholds are just recommendations and could require an adj
 The list of alerting rules is the following:
 * [alerts-health.yml](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts-health.yml):
   alerting rules related to all VictoriaMetrics components for tracking their "health" state;
-* [alerts.yml](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts.yml):
+* [alerts-single-node.yml](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts-single-node.yml):
   alerting rules related to [single-server VictoriaMetrics](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) installation;
 * [alerts-cluster.yml](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts-cluster.yml):
   alerting rules related to [cluster version of VictoriaMetrics](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/);

deployment/docker/compose-vm-cluster.yml

@@ -125,7 +125,7 @@ services:
     ports:
       - 8880:8880
     volumes:
-      - ./rules/alerts-cluster.yml:/etc/alerts/alerts.yml
+      - ./rules/alerts-cluster.yml:/etc/alerts/alerts-cluster.yml
       - ./rules/alerts-health.yml:/etc/alerts/alerts-health.yml
       - ./rules/alerts-vmagent.yml:/etc/alerts/alerts-vmagent.yml
       - ./rules/alerts-vmalert.yml:/etc/alerts/alerts-vmalert.yml

deployment/docker/compose-vm-single.yml

@@ -66,7 +66,7 @@ services:
     ports:
       - 8880:8880
     volumes:
-      - ./rules/alerts.yml:/etc/alerts/alerts.yml
+      - ./rules/alerts-single-node.yml:/etc/alerts/alerts-single-node.yml
       - ./rules/alerts-health.yml:/etc/alerts/alerts-health.yml
       - ./rules/alerts-vmagent.yml:/etc/alerts/alerts-vmagent.yml
       - ./rules/alerts-vmalert.yml:/etc/alerts/alerts-vmalert.yml