Containerize scraper and externalize credentials

Move DB host/user/password, Discord webhook, and log path to env vars
so the script can be deployed via Docker compose. Discord notifications
are now skipped silently when DISCORD_WEBHOOK is unset (the old
hardcoded webhook is removed pending rotation). Adds Dockerfile,
docker-compose.yml, requirements.txt, .env.example, and .gitignore for
the cyrion deployment.

Dockerfile

@@ -0,0 +1,10 @@
+FROM python:3.13-slim
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY attractions_api_logger.py .
+
+ENTRYPOINT ["python", "-u", "attractions_api_logger.py"]