[Feature request] Add ability to move individual tasks to different list

[digitalethics]

I'd like to see a feature implemented to be able to move individual tasks to different lists. Currently, the only way to do so is to edit the .txt files manually.

[JMoerman]

I was already planning on making this possible, but the UI needs quite a overhaul to properly support this. (It is not really something I can just bolt on to the current UI.)

A new (but not unrecognizable) UI is long overdue as

1. The UI doesn't really scale to larger window sizes.
2. The settings window is unnecessarily wide when using the Adwaita Gtk theme or similar themes.
3. No natural way to support more complex tasks.

• recurrence, time estimates, notes, etc...
• Not that relevant for todo.txt, as that format isn't really a great match for those things

4. Selecting a different task while the timer is running can be somewhat unintuitive.
5. I want to have a special list to which you can drag tasks that you want to work on for the day. A list of things you want to work on that day, not a list of what needs to get done in total.

Progress on this has been slow as I'm not a designer, I have to work on my thesis and I continue to think to much about things instead of writing something that is good enough.