feat: setup Docker + MariaDB pour déploiement self-hosted

- Dockerfile (PHP 8.2 Apache + pdo_mysql)
- docker-compose.yml (househub + mariadb + Traefik househub.nas.percolouco.com)
- schema.sql (22 tables + données initiales)
- includes/db.php adapté pour variables d'environnement
- .env.example, .gitignore, README mis à jour

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/apache.conf

@@ -0,0 +1,10 @@
+<VirtualHost *:80>
+    DocumentRoot /var/www/html
+    <Directory /var/www/html>
+        AllowOverride All
+        Require all granted
+        Options -Indexes
+    </Directory>
+    ErrorLog ${APACHE_LOG_DIR}/error.log
+    CustomLog ${APACHE_LOG_DIR}/access.log combined
+</VirtualHost>