Factorize document models into separate project

Summary

To facilitate the introduction of new and management of different document types, we need to create a separate project centralizing the declaration of document models.

Type

Improvement

Description

The newly created project (e.g. sybil-document-model) would contain all the models of the different possible type. Since we possess a "front" in Android and a backend in "python", we may want the declaration of model to be the most language agnostic possible which will likely then use tools to generate the aforementioned models in the different languages. As of now, we have models duplicated in both sybil-android and sybil-document-annotation alongside related DTOs. Please investigate and do the best way to approach this.

Acceptance Criteria / Definition of

• New project created
• Document models factorized in it
• Transcribe modifications into documentation