Reporter which calls a script or program at begin at end and during some RQG run.

0. Name of the reporter:
-----------------------
   "UserDefined" or similar

1. What is configurable
--------------------------
1.1 The timespan in seconds between the periodic reporter activities.
1.2 Path and name of the script or program to be called.
    Parameters other than the name of the file where the output has to be written
    do not have to be supported.
1.1 and 1.2 should be treated like any other RQG option.
1.3 The content of the script or program to be called has to be provided by the user.
    Its the responsibility of the user to ensure that it is
    - runnable on the OS used
    - provides any useful output

2. What has the reporter to do whenever it has to become active
---------------------------------------------------------------
On first activity only
2.1 Check if a value for timespan between periodic activities was
    assigned
    Yes -> Check if the value is reasonable (integer >= 0)
    No -> Use the default 10
    Check if the value is reasonable (integer >= 0)
       Yes -> Report the value or timespan between periodic activities
       No -> Error message
              + abort the RQG run with STATUS_ENVIRONMENT_ERROR
    Report the value or timespan between periodic activities
2.2 Check if a value for script or program was assigned
       No -> Error message
              + abort the RQG run with STATUS_ENVIRONMENT_ERROR
       Yes -> Check if this script or program exists
              No -> Error message
                    + abort the RQG run with STATUS_ENVIRONMENT_ERROR
              Yes -> Report the name of the script or program
2.3 Generate some path and file name
2.4 Remove this file if it already exists
    On error because of missing permission or file is a directory etc.
    -> Error message abort the RQG run with STATUS_ENVIRONMENT_ERROR
2.5 Create this file, write something into it and remove it
    On error > Error message abort the RQG run with STATUS_ENVIRONMENT_ERROR

    What is roughly (there might be changes after this check) ensured now:
    - Script or program exists
    - Outputfile can be created, written and removed

On any activity:
2.6 Maybe put values of interesting parameters like "vardir" into the
    environment.
2.7 Remove the output file if it already exists
2.8 Call the script or program and cause that its output is
    written into the file
2.9 Wait till the call of the script is finished but not longer than
    lets say 50 seconds.
2.10 Write the content of the file to stdout
2.11 Remove the output file

3. When has this reporter to become active
------------------------------------------
In case the reporter is in the list of reporters to be used
- direct before the SQL server gets started or gentest is called
- all n seconds (timespan between periodic activities)
- direct after a RQG run ending with status <> STATUS_OK.