core:Async Tasks cleaner utility...

Adding a utility to clean async tasks.
The utility enables to
 Display
     All async tasks
     Only Zombie tasks
  Delete
      All tasks
      All Zombie tasks
      A task related to a given task id
      A Zombie task related to a given task id
      All tasks related to a given command id
      All Zombie tasks related to a given command id
   Flags may be added (-C, -J) to specify if Job Steps & Compensation
data
   should be cleaned as well.

Usage: taskcleaner.sh [-h] [-s server] [-p PORT]] [-d DATABASE] [-u
USERNAME] [-l LOGFILE]  [-t taskId] [-c commandId] [-z] [-R] [-C]
[-J] [-q] [-v]

-s SERVERNAME - The database servername for the database  (def.
localhost)
-p PORT       - The database port for the database        (def.
5432)
-d DATABASE   - The database name                         (def.
engine)
-u USERNAME   - The admin username for the database.
-l LOGFILE    - The logfile for capturing output          (def.
taskcleaner.sh.log)
-t TASK_ID    - Removes a task by its Task ID.
-c COMMAND_ID - Removes all tasks related to the given Command
Id.
-z            - Removes/Displays a Zombie task.
-R            - Removes all Zombie tasks.
-C            - Clear related compensation entries.
-J            - Clear related Job Steps.
-q            - Quite mode, do not prompt for confirmation.
-v            - Turn on verbosity
(WARNING: lots of output)
-h            - This help text.

Change-Id: Idffc35eb5fca0e72c9e4c9e3a08c5b9799569fca
Signed-off-by: Eli Mesika <emesika@redhat.com>
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=891639
Signed-off-by: Eli Mesika <emesika@redhat.com>