Revert "[FEATURE] Add a disable/enable button to tasks overview"

This reverts commit 867e074db8c87be5781a06dc22ced5defad14faa

The enable/disable feature for the scheduler list view in its current
form is half baked and usability wise worse than before and reverted
now before the release of 6.1.
Reasons are, that the button only works in special cases as expected,
for example it does not change / work if a task is set to
'single execution' or if a task is beyond 'end date'.
Maybe the list overview needs to be restructured a bit to make this
feature usability wise more straight.

Change-Id: I36b5b87ced3fe2769f26bce9a4445d26e5bf1909
Relases: 6.2, 6.1
Related: #25631
Reviewed-on: https://review.typo3.org/20310
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn