Changes

* We have enabled [https://apptainer.org/docs/admin/main/user_namespace.html user namespaces] to support the operation of Apptainer<i>only on compute nodes</i>. You will not be able to test an Apptainer image on a login node. We recommend that If you make a habit of wish to do interactive testing Apptainers on compute nodes rather than login nodes, in case we have use <code>salloc</code> to disable user namespaces get an interactive shell on login nodes without notice for security reasonsa compute node.