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

Also, another way of creating the step iterator for this ``verifyIsFirstStepInParagraph`` function would be:
``odtDocument.createStepIterator(domPoint.node, domPoint.offset, [positionFilter], odfUtils.getParagraphElement(domPoint.node, domPoint.offset))``.

Then, the code can just assert that ``stepIterator.previousStep() === false``. The tiny upside of this is that iteration ceases as soon as the start of the paragraph is found.