Make it possible run a specific task by providing an additional
parameter -i and the uid of the task on the command line.

./typo3/cli_dispatch.phpsh scheduler -i <uid>

Use the parameter -f to force the execution even if the task is
disabled or no execution is scheduled.

Change-Id: I6226ea41fbb391a56f9eee3d3de919cc116157bc
Resolves: #31073
Relates: #38506
Releases: 6.0
Reviewed-on: http://review.typo3.org/12481
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Oliver Hader
Tested-by: Oliver Hader