slapos_cloud: add Computer Partition

master/bt5/slapos_cloud/PortalTypeAllowedContentTypeTemplateItem/allowed_content_types.xml

 <allowed_content_type_list>
  <portal_type id="Compute Node">
   <item>Certificate Login</item>
+  <item>Compute Partition</item>
   <item>ERP5 Login</item>
  </portal_type>
  <portal_type id="Compute Node Module">

master/bt5/slapos_cloud/bt/template_portal_type_allowed_content_type_list

 Compute Node Module | Compute Node
 Compute Node | Certificate Login
+Compute Node | Compute Partition
 Compute Node | ERP5 Login
 Hosting Subscription Module | Hosting Subscription
 Instance Tree Module | Instance Tree