Updated the nav bar with all the installations
* xref:installation/installation.adoc[Installation]
** xref:installation/minikube.adoc[Minikube]
** xref:installation/minishift.adoc[Minishift]
+** xref:installation/crc.adoc[Minishift]
** xref:installation/digitalocean.adoc[DigitalOcean Kubernetes Cluster]
** xref:installation/gke.adoc[Google Kubernetes Engine (GKE)]
** xref:installation/openshift.adoc[OpenShift]
** xref:installation/iks.adoc[IBM Kubernetes Service (IKS)]
+** xref:installation/k3s.adoc[Kind]
** xref:installation/kind.adoc[Kind]
** xref:installation/registry/registry.adoc[Configuring Registry]
*** xref:installation/registry/digitalocean.adoc[DigitalOcean]
