Tweaking map structure to reflect Mappy state

Currently Mappy does not have a more "DSL-type" declaration, instead
relying on an array structure.
Moving orcid_spec to lib spec

It was in model as part of the initial extraction.
Extracting ::Mappy reference to Orcid.mapper

Instead of the low-level implementation relying on an external
constant, point to a method in the existing namespace.
Configuring #register_mapping_to_orcid_work

Exposing Configuration#register_mapping_to_orcid_work to the
initializer.