[Draft] Create numbered and bulleted lists

This PR aims to add the creation of lists in a document. This only aims to support numbered and bulleted lists and not image bullet lists for now.

# TODO
* [x] Editor UI buttons
* [x] Detect list style at selection
* [ ] Ops for list insertion/removal
* [ ] OT support
* [ ] Convert selected text to a list or selected list back to text
* [ ] Default styles for numbered and bulleted lists

Pending pr #676, there will be a ``subscribeBatched`` that is better for this. With the recent merge paragraph features, the move cursor signal is now being fired twice or more per paragraph, which can cause some pretty significant performance issues.

No need to change this yet, but we'll need to revisit before the final patch can land.