Foto de usuario, Exchange, fixes varios, agregar post

al hacer signup: .post(user/signUp , { "username": "pepito", "email": "pepito@example", "password": "pepe", "picture": "data:image/webp;base64,UklGRkKXAABXRUJQVlA4IDaXAABwzQGdASotA+QBPlEm..." }

cuando un vendedor es aceptado, se hace user/addSeller para agregarlo localmente, deberiamos mandarle la foto del user comprador .post(user/addSeller, { "username": "pepeSeller", "email": "pepeSeller@example", "password": "pepe", "firstname": "pep", "lastname": "guardiola", "barCode": "asd", "personalId": "dsa", "picture": "data:image/webp;base64,UklGRkKXAABXRUJQVlA4IDaXAABwzQGdASotA+QBPlEm..." }

perfiles .get(user/profileCustomer/pepito@example)

.get(user/profileSeller/pepito@example)