Support due date first definition

[opatry]

Currently, due to poor dialog management on UI side, the due date first definition is not supported.

• Allow defining due date at task creation

• Allow defining due date when editing a task without due date

• Allow editing a due date from the edit dialog

• Allow editing a due date by clicking on it from the task list

• Add due date shortcuts in task row to reset/set today/set tomorrow/pick

• Add due date shortcuts in task editor to reset/set today/set tomorrow/pick (when unset)

• ℹ This will require Properly manage various task pane dialogs & bottom sheet #154