Backup functionality

Description

Add actions to create ldap data and config backup and restore it.

Ldap backup functionality consist of two different approaches. https://www.openldap.org/doc/admin24/maintenance.html

1. Backup data files, but it requires LDAP to be offline.
2. Backup ldif files using slapcat, which can be done during ldap accessibility.

Proposal

There is already ready to use container with implemented slapcat approach. It has cron configuration for backup retention as well as build in restore capabilities. This image is based on osixia/openldap, which we're using as our base image. We'll use it as a new base. https://github.com/osixia/docker-openldap-backup