"Page" itemControl bugs

[fongsean]

There is a slight issue on how the "page" itemControl is implemented previously.

From "Page" in https://hl7.org/fhir/extensions/ValueSet-questionnaire-item-control.html:

Indicates that the content within the group should appear as a logical "page" when rendering the form, such that all enabled items within the page are displayed at once, but items in subsequent groups are not displayed until the user indicates a desire to move to the 'next' group. (Header and footer items may still be displayed.) This designation may also influence pagination when printing questionnaires. If there are items at the same level as a 'page' group that are listed before the 'page' group, they will be treated as a separate page. Header and footer groups for a questionnaire will be rendered on all pages.

Few points to note based on this:

1. It would make sense to assume that a "page" can only be rendered at the top level.

2. There will not be a mixture of page items and non-page items anymore (as shown below).
   

3. If there is a page item at the top level, the entire questionnaire will be rendered as a paginated questionnaire.

---

On point 2, if there is a need for the mixture of page + non-page items to be brought back in the future, an API can potentially be exposed to configure its behaviour. Another issue has to be raised.