Hexagon: nice +5 for all login nodes

All users when logging into hexagon login nodes automatically will be "niced" to +5, each session on login node is limited to 100 running processes. This is not anyhow reflects on compute nodes. Jobs will not be affected.

This is done primarily to remove effect of one user high CPU tasks affects another users on the same login node.

Please give a feedback via support-uib@notur.no