Draft: Resolve "have an explicit data structure for cloze questions"

Goals

This MR will make cloze questions more approachable by giving them an explicit data structure

Non-goals

This MR will not make the new way the only way for defining cloze questions.

Implementation

We will extend the Cloze Question class to look for ID strings and then replace these with the generated cloze text from the question definition in the answers object

Closes #65