Feature: Fetch messages

Implement and test out read message feature. Basic use case would be:

Logged user, with valid jwt token, sends GET http request to /<:u_id> endpoint
If logged user follows user with id=u_id, return list of Message entity dtos where u_from is equal to jwt token id and u_to is equal to u_id. Otherwise return 403 (no jwt, no follow) or 404 response (u_id user does not exist)

This functionality should be integration tested.