Entity sections dispatched on :rdf/type

[simongray]

Basically, there should be a :default set of sections for most entities, but for certain ones there is an alternate set of sections dispatched on the entity's :rdf/type. Multimethods are probably the way to go? Perhaps in another namespace.

[simongray]

Still need to actually define the different section outputs, but at last the framework for doing so is in place.