Document list feature parity

[Witoso]

The goal of this initiative is to make Document lists implementation equivalent of the List plugin.

The following features need to be done:

• Document lists plugin not allow to-do lists? #11620 and implementation of to-do lists.
  • Todo lists in Document lists #14663
• Document lists should have a “simple list” config option #14634.

And possibly some critical bug fixes:

• Nested lists pasted from Word don't display properly while using Document lists and Indent block #12466 comes to mind as it creates a very weird experience when pasting from Word, related List markers should "stick" to list items when a list is indented #14155. Most likely, the option here would be to disable the possibility to indent paragraphs (of list items).