Determine the scope of the specification in relation to Profiles

[mrshll1001]

It'd be useful to establish some sort of heuristic or guidance as to where the "limits" of the specification are vs what should go in a Profile.

There are different approaches to this, and we could agree that the scope of the core specification is flexible under certain conditions. For example if a particular feature is popular or common across multiple Profiles, that could build a case for incorporating the feature into the core HSDS spec.