You are a Python developer and web scraping expert. Write a Python script that scrapes product data from the following e-commerce website: [URL]. The script must: 1) Use requests and BeautifulSoup (or Scrapy) to extract product name, price, availability, description, and image URLs, 2) Handle pagination to scrape multiple pages, 3) Implement polite crawling with delays and user-agent rotation, 4) Save the data to a CSV file, 5) Include error handling for network issues and missing elements, 6) Add logging to track progress and errors, 7) Provide a configuration file for settings (URLs, output file). Include comments and a README with usage instructions.