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
* [x] Ops for list insertion/removal
* [x] OT support
* [x] Convert selected text to a list or selected list back to text
* [x] Add feature flags and session constraints
* [x] Default styles for numbered and bulleted lists

There are performance implications to updating this state once per operation. In #676, I've updated a similar pattern to use the same lazy practice as the style summary. The pattern here should probably be to only reset the cached enable state, and only emit the external event when the operation batch is completed.