Split database entities and response serialized objects (DTO)

[kinow]

It's normally considered a bad practice to have the database model classes also being used to send data to the user in responses.

It's better - and IMHO easier to maintain - to have the database model classes with its single responsibility, and move all de/serialization specifics to DTO's (or any other acronym like VO/POJO/DO/etc used in the project).

Description

Part of #254 . Realized I was having to deal with the MongoDB specifics and also with how data is de/serialized :disappointed_relieved: It would have been a bit simpler should these two were separated entities.

Expected Behavior

Separate classes, separate concerns.

Actual Behavior

Possible Fix

Steps to Reproduce

NA

Context

Your Environment

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