Move finished tasks into "done" folder

[Crunchyman-ralph]

• When a task is done, it doesn't make sense for it to clutter up the root folder "tasks", we should move it to a done folder.

[eyaltoledano]

Good idea. We'll need to adjust the rest of the task-manager and dependency-manager files to properly look into the done folder as well. Typically though you wouldn't ever need to interact with the task files directly so i'm not sure how this adds value beyond just looking nice

[eyaltoledano]

Not doing this. You can just use the filtering option.