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

Have removed the API comment. By default all features are enabled in the local editor and no features are specifically disabled. Should we disable the list editing by default for now in the local file editor?