Moved TaskQuery utility in to tasks own query class: `get_tasks` -> `by_ids`.
QueryUtility: Dropped no longer used methods.
Dropped support for catalog listings in get_selected_items helper.

All tasklistings are Globalindex listings, therefore the support for catalog listings are needless.
QueryUtility: Dropped no longer used methods
Dropped no longer used ITaskQuery utility:

All queries, which are still in use, has been moved to the Task query
class (see previous commits for more information).
Dropped no longer used query method `tasks_by_ids`.