Merge sections in System Requirements

* Merge public and private cloud network requirements
* Merge public and private clout node requirements
* Requirements for each public cloud are in a
  variable list

xml/deployment_preparation.xml

@@ -466,7 +466,7 @@ caasp3-stack-admin|10.81.1.51</screen>
  </sect1>
 
  <sect1 xml:id="sec.deploy.preparation.disk_images">
-  <title>Installing from Disk Images</title>
+  <title>Installing from Virtual Disk Images</title>
  <para>
   For building clusters from virtual machines on supported
   hypervisors, it is not necessary to individually install each
@@ -795,20 +795,9 @@ suse_caasp:
     <step>
      <para>
       Read the special system requirements for public cloud
-      installations:
+      installations in <xref
+      linkend="sec.deploy.requirements.public_cloud" />.
      </para>
-     <itemizedlist>
-      <listitem>
-       <para>
-        <xref linkend="sec.deploy.requirements.public_cloud" />.
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-        <xref linkend="sec.deploy.requirements.public_cloud_network" />.
-       </para>
-      </listitem>
-     </itemizedlist>
     </step>
     <step>
      <para>