Publication type advice changes

Changes to publication type advice for Notices, Decisions and
Regulations.
Move publication type Regulations to Use discouraged group.
Fix bug with showFormatAdviceForSelectedSubtype

Fix bug with showFormatAdviceForSelectedSubtype not removing
publication type advice after the publication type selection is changed.
Merge pull request #1791 from alphagov/publication-type-guidance

Publication type guidance
Untangle Publishing API from Panopticon registration

These are not the same things so we shouldn't use the same decorator class,
especially given Panopticon will eventually be retired.