Following MDL-63580 this now finally deprecates and removes the class
\tool_task\run_from_cli, please use \core\task\manager.

Following MDL-63580 this now finally deprecates and removes
 - admin/tool/task/cli/schedule_task.php, use admin/cli/scheduled_task.php
 - admin/tool/task/cli/adhoc_task.php, use admin/cli/adhoc_task.php

Also mentions and references to the old CLI scripts are updated to
point to the new counterparts.

Signed-off-by: Daniel Ziegenberg <daniel@ziegenberg.at>