feat!: Add Authelia for authentication and Redis for session storage

- Introduced Redis service for session management with health checks.
- Added Authelia service for user authentication with necessary environment variables.
- Configured Traefik to use Authelia as middleware for various services.
- Created Authelia configuration file with session, storage, and access control settings.
- Added user database for Authelia with an example admin user.

authelia/configuration.yml

@@ -0,0 +1,83 @@
+# Authelia Configuration File
+# Documentation: https://www.authelia.com/configuration/
+
+# Default configuration options affecting multiple sections.
+default_redirection_url: ${AUTHELIA_DEFAULT_REDIRECT_URL}
+
+# Server settings (listening address, paths, etc.)
+server:
+  host: 0.0.0.0
+  port: 9091
+
+# Logging configuration
+log:
+  level: info
+  format: text # or json
+
+# Session configuration
+session:
+  name: authelia_session
+  secret: ${AUTHELIA_SESSION_SECRET}
+  expiration: 1h # Adjust as needed
+  inactivity: 5m # Adjust as needed
+  domain: ${AUTHELIA_SESSION_DOMAIN} # Set from .env
+  redis:
+    host: redis
+    port: 6379
+    password: ${AUTHELIA_REDIS_PASSWORD}
+    database_index: 0
+
+# Regulation (brute force protection)
+regulation:
+  max_retries: 3
+  find_time: 2m
+  ban_time: 5m
+
+# Storage (for user preferences, etc. - encrypted using storage key)
+storage:
+  encryption_key: ${AUTHELIA_STORAGE_ENCRYPTION_KEY}
+  local:
+    path: /config/db.sqlite3 # Example using SQLite for simple storage needs
+
+# Authentication backend (using file-based user database)
+authentication_backend:
+  file:
+    path: /config/users_database.yml
+    password:
+      algorithm: argon2id # Recommended hashing algorithm
+      iterations: 1
+      memory: 1024 # MiB
+      parallelism: 8
+      salt_length: 16
+      key_length: 32
+
+# Access control rules
+access_control:
+  default_policy: deny # Deny access by default
+  rules:
+    # Rule to allow authenticated users access to the domain
+    - domain: ${AUTHELIA_SESSION_DOMAIN}
+      policy: one_factor # Requires username/password
+
+# Notifier (Optional, for password resets, etc. - configure if needed)
+# notifier:
+#   smtp:
+#     address: smtp.example.com:587
+#     username: user@example.com
+#     password: password
+#     sender: Authelia <authelia@example.com>
+#     subject: "[Authelia] {title}"
+#     startup_check_address: test@authelia.com
+
+# JWT configuration (used for forwardAuth)
+jwt_secret: ${AUTHELIA_JWT_SECRET}
+
+# Identity Providers (None configured for this setup)
+identity_providers:
+  oidc: null # Explicitly disable OIDC
+
+# Enable registration (requires manual approval by editing users_database.yml)
+# Set 'enable: true' to allow users to register.
+# They will be added to users_database.yml commented out or with disabled: true.
+# registration:
+#   enable: false # Set to true to enable registration form