tech(docker): rename fake data writers

docker/blocks/graphite/fig

@@ -8,7 +8,7 @@ graphite:
     - /etc/localtime:/etc/localtime:ro
     - /etc/timezone:/etc/timezone:ro
 
-fake-data-gen:
+fake-graphite-data:
   image: grafana/fake-data-gen
   net: bridge
   environment:

docker/blocks/influxdb/fig

@@ -5,7 +5,7 @@ influxdb:
     - "8083:8083"
     - "8086:8086"
 
-fake-data-gen:
+fake-influxdb-data:
   image: grafana/fake-data-gen
   net: bridge
   environment:

docker/blocks/opentsdb/fig

@@ -3,7 +3,7 @@ opentsdb:
   ports:
     - "4242:4242"
 
-fake-data-gen:
+fake-opentsdb-data:
   image: grafana/fake-data-gen
   net: bridge
   environment:

docker/blocks/prometheus/fig

@@ -6,7 +6,7 @@ prometheus:
   volumes:
     - /var/docker/prometheus:/prometheus-data
 
-fake-data-gen:
+fake-prometheus-data:
   image: grafana/fake-data-gen
   net: bridge
   ports: