Replace Hardcoded HTTP Status values with http.HTTPStatus

[maxachis]

Currently, all parts of the backend code which return responses provide the HTTP status code as an integer. For example, in Login.py:

return {"message": "Invalid email or password"}, 401

When designing responses or interpreting existing responses, this means I have to have a tab open to interpret different HTTP Status Codes.

A more readable option would be to replace the HTTP Status codes with enums, conveniently provided by native python library http as HTTPStatus. To give an example for the above code:

return {"message": "Invalid email or password"}, HTTPStatus.UNAUTHORIZED