Make draft of internal class structure

[oliviadargel]

User story

1. As a backend developer
2. I want to make a draft for an internal structure
3. So that I can implement it for storing the response from the NLP component

Acceptance criteria

• all current elements of the JSON returned by NLP component are taken into consideration
• draft is uploaded in this issue as comment and in Documentation folder

Definition of done

• Added only after week 5
• The same for all features

[oliviadargel]

Hints:

• see get_json function here
• discuss with NLP Team for compatibility of types