Use ppx import in ood

[cuihtlauac]

Move @@deriving attributes from Data_intf to ood/lib files

Module Data_intf does not need to expose Yaml parsing or
pp/show functions at runtime. This is only used when crunching
the data. Types are duplicated in ood using ppx_import and
ppx_deriving is applied to those definitions.

Staged preprocessing is used.

Some modules aren't moved yet:

• Academic_institution
• Blog
• Governance
• Video
• Planet

The former four because they have field-level attributes which
aren't supported by ppx_import

The latter because it depends on Blog and Video