better default configuration and content in test ldap

Merge branch 'master' of https://github.com/kakwa/ldapcherry

adding creation of a ext4 partition

adding methods add_user and del_user ...

* adding add_user
* adding del_user
* adding unit tests
* adding configuration parameters for adding users

implementing search users ...

* adding search
* adding unit tests

adding test cases and reworking test env