Devenv: adds grafana block with a customizeable version (#22867)

The grafana block is pre-configured with the devenv datasources and
dashboards and will work with any other blocks out of the box.

devenv/docker/blocks/grafana/.env

@@ -0,0 +1 @@
+grafana_version=6.6.2

devenv/docker/blocks/grafana/docker-compose.yaml

@@ -0,0 +1,8 @@
+  grafana:
+    image: grafana/grafana:${grafana_version}
+    ports:
+      - "3001:3000"
+    volumes:
+      - "./dashboards.yaml:/etc/grafana/provisioning/dashboards/dashboards.yaml"
+      - "./dev-dashboards:/usr/share/grafana/devenv/dev-dashboards"
+      - "./datasources_docker.yaml:/etc/grafana/provisioning/datasources/datasources.yaml"

devenv/docker/blocks/prometheus2/docker-compose.yaml

@@ -1,18 +1,15 @@
   prometheus:
     build: docker/blocks/prometheus2
-    network_mode: host
     ports:
       - "9090:9090"
 
   node_exporter:
     image: prom/node-exporter
-    network_mode: host
     ports:
       - "9100:9100"
 
   fake-prometheus-data:
     image: grafana/fake-data-gen
-    network_mode: host
     ports:
       - "9091:9091"
     environment:
@@ -20,12 +17,10 @@
 
   alertmanager:
     image: quay.io/prometheus/alertmanager
-    network_mode: host
     ports:
       - "9093:9093"
 
   prometheus-random-data:
     build: docker/blocks/prometheus_random_data
-    network_mode: host
     ports:
       - "8081:8080"