Move models from EE to core code
Summary
Currently the database schema incorporates models from both core and EE code So all installation have the database parts of all models available always.
Please also move all models to the core, at least the field definition parts.
Improvements
It allows community contributions on all models, even if the frontend parts are missing.
I already thought about contributing Debian package support, but this needs the packages models and maybe some other basic stuff to be available.
Risks
Involved components
Optional: Intended side effects
This will re-license code.