Migrate all Docker image references to Docker Hub (prometheus#4864)

Signed-off-by: noqcks <benny@noqcks.io>

README.md

@@ -46,11 +46,11 @@ Debian packages [are available](https://packages.debian.org/sid/net/prometheus).
 
 ### Docker images
 
-Docker images are available on [Quay.io](https://quay.io/repository/prometheus/prometheus).
+Docker images are available on [Quay.io](https://quay.io/repository/prometheus/prometheus) or [Docker Hub](https://hub.docker.com/r/prom/prometheus/).
 
 You can launch a Prometheus container for trying it out with
 
-    $ docker run --name prometheus -d -p 127.0.0.1:9090:9090 quay.io/prometheus/prometheus
+    $ docker run --name prometheus -d -p 127.0.0.1:9090:9090 prom/prometheus
 
 Prometheus will now be reachable at http://localhost:9090/.
 

docs/installation.md

@@ -18,12 +18,13 @@ the respective repository.
 
 ## Using Docker
 
-All Prometheus services are available as Docker images under the
-[prom](https://hub.docker.com/u/prom/) organization.
+All Prometheus services are available as Docker images on
+[Quay.io](https://quay.io/repository/prometheus/prometheus) or
+[Docker Hub[(https://hub.docker.com/u/prom/).
 
 Running Prometheus on Docker is as simple as `docker run -p 9090:9090
-prom/prometheus`. This starts Prometheus with a sample configuration and
-exposes it on port 9090.
+prom/prometheus`. This starts Prometheus with a sample
+configuration and exposes it on port 9090.
 
 The Prometheus image uses a volume to store the actual metrics. For
 production deployments it is highly recommended to use the