Adding Presenter conversion function
Adding Entity#to_presenter method

The other DataDefinitions would benefit from this, but for now they
aren't needed as the PresentedFieldsets appears to convert them.
Updating TranslationKeyFragment conversion

Instead of relying on the objects work type, instead rely on the
presented object. After all the presented object may very well
implement a #to_translation_key_fragment method which very likely
delegates to the object's #work_type
Removing forced presentation structure

Given that the spec is generating what passes as a presentation
structure, I'll lean on that instead of hand crafting my own.
Adding test for WorkType() conversion

I was not testing a thing that was not empty?
Removing the plurality of the description

Because the documentation output of rspec is a little clearer.

[skip ci]
Using module function instead of instance

This adds one more level of code coverage.
Fixing individually running spec
Adding EntityForm#valid? tests
@WIP