Refactor Scraper Dockerfile and Add Entrypoint Script

- Replaced inline entrypoint script creation in the Dockerfile with a separate entrypoint.sh file for better maintainability and clarity.
- The new entrypoint script handles one-time scraping with date range support, improving the scraper's functionality and usability.

cmd/scraper/entrypoint.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+if [ "$SCRAPER_ONETIME" = "true" ] && [ -n "$FROM_DATE" ] && [ -n "$TO_DATE" ]; then
+  exec /app/scraper-build -onetime -from "$FROM_DATE" -to "$TO_DATE"
+else
+  exec /app/scraper-build
+fi
+