Real time config support

WIP

* [ ] Integration tests covering the module's functionality
* [ ] Switch to seeding `cn=config` from `slapd.conf` as an interim measure
* [ ] Configure `cn=config` directly via LDAP, dropping `slapd.conf`
* [ ] Integrate support for [managing directory via custom resources](https://github.com/gtmtechltd/puppet_ldapdn)
* [ ] Add support for loading schemas from `.schema` or `.ldif` files (custom resource type)