[FEATURE] Add Progress bar for task progress

Some tasks may want to provide the user with information about how
far progress of their jobs has come.

Currently there is no way to do this in a nice way. The existing
method getAdditionalInformation() does not allow to output HTML.

Fixes: #36802
Releases: 6.0
Change-Id: I86877b3a3ec70e8c6ef5deae7e54442c35afada3
Reviewed-on: http://review.typo3.org/10946
Reviewed-by: Philipp Gampe
Reviewed-by: Nikolas Hagelstein
Reviewed-by: Mattias Nilsson
Tested-by: Mattias Nilsson
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert