(ITS#9111) new feature:using the encrypted text to save password for read only user

Full_Name: Nannan Song Version: 2.4.44 OS: SUSE URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (221.226.97.96)

When LDAP is used to manage user and user group information, openldap only supports the configuration of the plain text password of the read-only user in the '/etc/ldap.conf/'. The password of the read-only user only supports plain text storage. so there is a security issue that the authentication credential file is readable to all users. Now we hope ldap can support the feature that using the encrypted text to save password for read only user.