Issue31 - Add memberOf fix-up task
    
    Description:
    - Implement a new-style Task class based on DSLdapObject.
    - Create the memberof fix-up task class.
    - Add dsconf support for calling the task.
    - Write a functional test for testing the fix-up task.
    - Small bug fixes on the test utils for plugin tests.
    - Replace some "from foo import *" imports with explicit imports.
    
    https://pagure.io/lib389/issue/31
    
    Author: Ilias95
    
    Review by: wibrown (Thank you, great work!)