slapos_cloud: Only set SITE prefix if organisation has a specific role

master/bt5/slapos_cloud/SkinTemplateItem/portal_skins/slapos_cloud/Organisation_init.py

 portal = context.getPortalObject()
 
-reference = "SITE-%s" % portal.portal_ids.generateNewId(
+if context.getRole() == "host":
+  reference_prefix = "SITE"
+else:
+  reference_prefix = "O"
+
+reference = "%s-%s" % (reference_prefix, portal.portal_ids.generateNewId(
     id_group='slap_organisation_reference',
-    id_generator='uid')
+    id_generator='uid'))
 
 context.edit(reference=reference)