Add default values in for ou rdn when they are not in the LDAP configuration

At line https://gitlab.fusiondirectory.org/fusiondirectory/fusiondirectory-tools/-/blob/dev/src/FusionDirectory/Tools/Setup.php#L876 we see that we have no default value.

It will be better to have a default so we avoid a crash. The default values are the following one.

fdUserRDN: ou=people
fdGroupRDN: ou=groups
fdTokenRDN: ou=tokens
fdRecoveryTokenRDN: ou=recovery,ou=tokens
fdOrchestratorTokenRDN: ou=orchestrator,ou=tokens
fdReminderTokenRDN: ou=reminder,ou=tokens