This brings a significant refactor to how
we handle `import_export.yml`, merge it with EE
and how we handle that for reader and saver.

This is meant to simplify the code, and remove
a ton of conditions to handle different models
of the structure.

This is also meant to prepare the structure
to extend it much easier, like adding `preload:`
or additional object types when needed.

This does not change the behavior of import/export,
rather unifies and simplifies the current implementation.