Creating an `hacluster` User and `haclient` Group for Pacemaker

Pacemaker tries to use the user and group hacluster:haclient when root access is not needed for an operation. So does Booth. Sometimes you might need to (re)create this user and group.

# getent group haclient >/dev/null || groupadd -r haclient -g 189
# getent passwd hacluster >/dev/null || \
   useradd -r -g haclient -u 189 -s /sbin/nologin -c cluster user hacluster

Reviewed 2020/12/14 - DGT