Improvements to answer saving process

[struan]

At the moment it's easy to be confused about whether an answer has been saved.

e.g. because it saves valid questions but not invalid ones it's not always clear that all the fields for an invalid question have not been saved so it's possible to think that only the invalid field hasn't been saved and lose work.

Need to revisit this to make it clear what has been saved, what has not. Ideally this should default to saving as much as possible to avoid data loss.

[struan]

Maybe the way to do this is to have some JS in the background submitting the current form to see if it's valid and when it is putting little green checks next to it.

Maybe in an ideal world the DB would record if an answer was complete and that would be used for the progress count rather than presence of an answer but very much nice to have.