- Remove sudoers file 'zabbix' in favour of new IPFire managed
'zabbix_agentd' and user managed 'zabbix_agentd_user' which is
included in the backup
- Provide migration of old sudoers file 'zabbix' or 'zabbix.user' to
new zabbix_agentd_user sudoers file if it was modified by user.
Signed-off-by: Robin Roevens <robin.roevens@disroot.org>
