Delete insecure external link. (#19567)

* Delete insecure external link.

Delete insecure external link. The website hasn't an HTTPS version.
Also, the project (https://github.com/kubernetes-retired/contrib/tree/master/node-perf-dash) will be archived 2 years ago.

* Update reserve-compute-resources.md

* Remove link to blog for the same reason.

Author: francobep

content/en/docs/tasks/administer-cluster/reserve-compute-resources.md

@@ -94,13 +94,7 @@ be configured to use the `systemd` cgroup driver.
 `kube-reserved` is meant to capture resource reservation for kubernetes system
 daemons like the `kubelet`, `container runtime`, `node problem detector`, etc.
 It is not meant to reserve resources for system daemons that are run as pods.
-`kube-reserved` is typically a function of `pod density` on the nodes. [This
-performance dashboard](http://node-perf-dash.k8s.io/#/builds) exposes `cpu` and
-`memory` usage profiles of `kubelet` and `docker engine` at multiple levels of
-pod density. [This blog
-post](https://kubernetes.io/blog/2016/11/visualize-kubelet-performance-with-node-dashboard)
-explains how the dashboard can be interpreted to come up with a suitable
-`kube-reserved` reservation.
+`kube-reserved` is typically a function of `pod density` on the nodes.
 
 In addition to `cpu`, `memory`, and `ephemeral-storage`, `pid` may be
 specified to reserve the specified number of process IDs for