Configure LDAP (ldapd) on OpenBSD 6.8

LDAP "Lightweight Directory Access Protocol" is an open and cross platform protocol used for directory services authentication. On MS Windows Servers people typically use "Active Directory", and on other servers OpenLDAP is typically used. The LDAP protocol is a more-robust and secure means of authentication compared to NIS/YP.

OpenBSD 6.8 has the ldapd daemon, which is developed by OpenBSD developers.

We will use LDAP to manage SIP accounts on our Asterisk 16 server.