fix: use Authelia environment variables instead of YAML substitution

- Set AUTHELIA_IDENTITY_VALIDATION_RESET_PASSWORD_JWT_SECRET in compose
- Set AUTHELIA_SESSION_SECRET in compose
- Set AUTHELIA_STORAGE_ENCRYPTION_KEY in compose
- Set AUTHELIA_STORAGE_POSTGRES_PASSWORD in compose
- Remove variable syntax from configuration.yml
- Authelia reads these directly from environment variables

net/compose.yaml

@@ -272,9 +272,10 @@ services:
     restart: unless-stopped
     environment:
       TZ: ${TIMEZONE:-Europe/Berlin}
-      AUTHELIA_JWT_SECRET: ${AUTHELIA_JWT_SECRET}
+      AUTHELIA_IDENTITY_VALIDATION_RESET_PASSWORD_JWT_SECRET: ${AUTHELIA_JWT_SECRET}
       AUTHELIA_SESSION_SECRET: ${AUTHELIA_SESSION_SECRET}
       AUTHELIA_STORAGE_ENCRYPTION_KEY: ${AUTHELIA_STORAGE_ENCRYPTION_KEY}
+      AUTHELIA_STORAGE_POSTGRES_PASSWORD: ${DB_PASSWORD}
     volumes:
       - authelia_config:/config
       - ./authelia:/etc/authelia:ro