Create a new Form structure

[prashtx]

The current Form document structure was pretty ad hoc, and it has resulted in some messy and fragile code. In particular, there's some lack of consistency among radio questions, checkboxes, and other types. We also tend not to process the form recursively (partly for mobile performance reasons), so the tree structure is not as helpful as intended.

[prashtx]

To what extend do we want to comingle layout with the data/structural aspects? Do we want to support spacers?

What's a future-proof way to support contextual help info that might contain imagery? Embedding data URIs removes any dependency on hosting and makes offline mode simpler, but we'd increase the size of a form document substantially.

[prashtx]

Conditional questions should be triggered based on a simple but flexible DSL, so that we can condition on previous answers, aspects of the base data, or some future requirement (like time of day).

[hampelm]

We might want to group questions into logical groups (like pages) at some point

[hampelm]

This is much more on the UI / implementation side, but a very large percent of data quality problems come from changing question and answer names. Any question change creates a new column. Answer values can be absurdly long. Answer changes can bifurcate the data needlessly. We should find a way to stabilize these more. That might include exposing field names to users.