Task cancelling support
The ability to cancel running actions within a task was added here http://projects.theforeman.org/issues/5719.
This is more low-level stuff that allows "unstuck" the system, when something goes wrong and it seems there is no
other way to solve the situation.
However, in some cases canceling might be something that a user should be able to do from the basic UI (without
need to go to the task details page/running steps page: for example the repository syncing: it should be allowed
only for cases when canceling doesn't cause the resource to be locked (such as repo sync).
The tasks, that would support the cancelling would have the option directly in the task details, without
need to understand more details about the task.