SRVCOM-426: Update Installation Doc for 0.4.0 release with installer details (#22)

* Update Installation Doc for 0.4.0 release with installer details and broken MAISTRA comment

* Update knative-OCP-4x.md

* Update con_knative-OCP-4x.adoc

Author: nebelsprachen

common/con_knative-OCP-4x.adoc

@@ -14,8 +14,12 @@ You will need cluster administrator privileges to install and use Knative on an
 
 === Supported platform version
 
+IMPORTANT: Installation requires the OpenShift version `0.14.0` installer or later. Using the link:https://github.com/openshift/installer/releases[latest version installer] is recommended.  
+
 [cols="50,50"]
 |===
 |** Platform**     | **Supported versions**   
 | OpenShift    | 4.0 Developer Preview
 |===
+
+NOTE: Long-running clusters are not supported in this release.

knative-OCP-4x.md

@@ -11,10 +11,14 @@
 
 > **NOTE:** This Knative on OpenShift preview is only available by using the OpenShift 4.0 developer preview. You will require a Red Hat Developers login to try this. Visit [try.openshift.com](https://try.openshift.com/) for getting started information.
 
+> **IMPORTANT:** Installation requires the OpenShift version `0.14.0` installer or later. Using the [latest version installer](https://github.com/openshift/installer/releases) is recommended.  
+
 | Platform        | Supported versions           |
 | ------------- |:-------------:|
 | OpenShift      | [4.0 Developer Preview](https://try.openshift.com/)		|
 
+> **NOTE:**  Long-running clusters are not supported in this release.
+
 ## Installing Knative on an OpenShift cluster using the script provided
 
 1. Login to the cluster using your admin credentials.