Adding system user barbican

The patch creates barbican user to be used during barbican
installation due to the fact that since Queens while secret
db sync is executed by salt with uid root and nss_db is created
as well during this process therefore as a result nss_db is
inaccessible for barbican process.

Change-Id: Idc387e7ae10f7c1084c75f2011abdc8081088bda
Related-PROD: PROD-23538
2 files changed