According to Django 1.11 documentation if there are 404.html and 500.html
pages in templates root directory then it loads them in case of 404 or
500 errors without any extra code needed. More details in:
https://docs.djangoproject.com/en/1.11/ref/views/#error-views
Signed-off-by: Alfredos-Panagiotis Damkalis <fredy@fredy.gr>