[Nova] Switch to vsphere.local user

The previously-used `localos` user will go away with vSphere 8.
Therefore, we switch to a user of the `vsphere.local` domain.

openstack/nova/values.yaml

@@ -288,7 +288,7 @@ scheduler:
 
 compute:
   defaults:
-    host_username: m3novaapiuser
+    host_username: m3novaapiuser@vsphere.local
     default:
       max_concurrent_builds_per_project: 20
       max_concurrent_builds: 50