Vioscreen state transforms

The raw vioscreen FFQ data come down from the Viocare API in structured JSON objects. Each aspect of the FFQ (food components, percent energy, etc) is structured somewhat differently. One of the key steps in the process of formally representing the FFQ data in the microsetta database is to transform these “raw” representations, into forms that are suitable for SQL table structures. This issue is scoped to cover the process of transforming these JSON objects into to-be-defined Model objects.

The specific models that should be created are:

- [ ] `VioscreenUser`
- [ ] `VioscreenSession`
- [ ] `VioscreenDietaryScores`
- [ ] `VioscreenFoodComponents`
- [ ] `VioscreenFoodConsumption`
- [ ] `VioscreenMPEDs`
- [ ] `VioscreenPercentEnergy`
- [ ] `VioscreenSupplements`
- [ ] `VioscreenEatingPatterns`
- [ ] `VioscreenFFQ` (a composite model reflecting the individual pieces)

The issue names no files, tests, or entry points. Start by locating the Viocare API raw JSON handling and the project's existing SQL model conventions, then map each listed representation to a model and define the composite VioscreenFFQ. Done means all listed models are specified and the raw objects can be represented in the database.

Written by the indexing model from the issue text.