Remove default page status

[Healthedata1]

Currently, all ig page standard statuses default to "informational". For example:

This behaviour is unexpected and leads to confusion for the reader when they see conformance language in the page content. Propose removal of the default behavior and replace it with QA warnings that the page status is empty and a link to instructions on how to set the page statuses.

[lmckenzi]

We don't want to change the default behavior here. It would be a huge pain to have to explicitly flag all pages and we believe that most pages defaulting to 'informative' is correct.

In the short term, we will add a warning if an IG is STU or normative and there are no pages that are marked as having that status. In the longer term, we'll check the content of the pages for conformance verbs (upper-case SHALL/SHOULD/MAY) and if it finds those on a page that isn't marked as STU or normative, it'll yell and will similarly yell if it finds a page that's STU or normative and doesn't have any of those conformance terms.