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.

docker-compose.yml

@@ -0,0 +1,14 @@
+services:
+  scraper:
+    build: .
+    image: kuh-no-bowls:latest
+    container_name: kuh-no-bowls-scraper
+    env_file: .env
+    environment:
+      LOG_PATH: /var/log/kuh-no-bowls/kuh-no-bowls.log
+      TZ: America/New_York
+    volumes:
+      - knb_logs:/var/log/kuh-no-bowls
+
+volumes:
+  knb_logs: