We need to rewire the autosave mechanism with the visual editors transaction events based on the CX-VE integration architecture
In https://gerrit.wikimedia.org/r/#/c/379213/, basic autosave support implemented.
It connects the update events for the section nodes to the translation update events and do autosave. Section HTML content is extracted from the source and target
models. Some refactoring and utility method additions done for that.
Many sections throw errors while extracting content, for example sections with references. That need investigation and follow up fixes.