Change compute reference to login

Because compute and login nodes are basically the same except login node does not need slurmd and we don't use compute image anywhere. So use it to build login image and change its references in CI script

ansible/group_vars/all

@@ -81,3 +81,11 @@
   findtime: 600
   bantime: 1200
   fail2ban_white_list: "127.0.0.1/8"
+
+# Node Exporter
+  enable_node_exporter: false
+  node_exporter_ver: "1.8.2"
+  node_exporter_filename: "node_exporter-{{ node_exporter_ver }}.linux-amd64"
+  node_exporter_user: node_exporter
+  node_exporter_group: node_exporter
+  node_exporter_port: 9100