[chores] Updated tldextract and made ROOT_DOMAIN logic consistent

A variable called ROOT_DOMAIN was computed with different
methods in nginx and base image.
The approach using the tldextract library seems more robust,
therefore I decided to update the library and change the
base image settings code accordingly.

images/common/openwisp/settings.py

@@ -3,6 +3,7 @@
 import os
 import sys
 
+import tldextract
 from openwisp.utils import (
     env_bool,
     is_string_env_bool,
@@ -28,8 +29,8 @@
 BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 SECRET_KEY = os.environ['DJANGO_SECRET_KEY']
 DEBUG = env_bool(os.environ['DEBUG_MODE'])
-ROOT_DOMAIN = f'.{".".join(os.environ["DASHBOARD_DOMAIN"].split(".")[1:])}'
 MAX_REQUEST_SIZE = int(os.environ['NGINX_CLIENT_BODY_SIZE']) * 1024 * 1024
+ROOT_DOMAIN = '.' + tldextract.extract(os.environ["DASHBOARD_DOMAIN"]).registered_domain
 INSTALLED_APPS = []
 
 if 'DJANGO_ALLOWED_HOSTS' not in os.environ:

images/openwisp_base/requirements.txt

@@ -8,6 +8,7 @@ django-cors-headers~=3.1  # allows 3.x and > 3.1
 django-pipeline~=2.0  # allows 2.x
 uwsgi~=2.0.20
 django-celery-email~=3.0.0
+tldextract~=5.1.2
 # these add support for object storage
 # (eg: Amazon S3, GCS)
 django-storages~=1.12.3

images/openwisp_nginx/requirements.txt

@@ -1 +1 @@
-tldextract~=3.2.0
+tldextract~=5.1.2