Ticket 47584: CI tests: add backup/restore of an instance
    
    Bug Description:
         A test case or a test suite needs to be isolated from side effects of others
         test cases run previously. For this we need to run a test case with
         "clean" instances.
    
    Fix Description:
         Creating/deleting instances is consuming time and could take much more
         time than the test case itself.
    
         The idea, is to create a kind of instance backup file. This backup file
         contains all components of the instance: config, schema, database
         environement, database files, certificates/keys...
    
         Before running a test case, the test reinit the instance it needs from
         this backup. So it gets rapidely  "clean" instances
    
    https://fedorahosted.org/389/ticket/47584
    
    Reviewed by: Rich Megginson, Roberto Polli (Thank you both for your help/patience !)
    
    Platforms tested: F19
    
    Flag Day: no
    
    Doc impact: no