Enhacement 2 (read EAN products from HTML file)

[areee]

• Add new dependency (intl) & use it with csv file name
• Add new gitignored file (*.html)
• Add 'assets/files/' directory where to get .txt & save .csv
• Add 'html' dependency & start 'web scraping' with local html file
• Update '_loadHtmlFromAssets' method to get EAN codes
• Move all methods from 'main' file to own files
• Some refactoring (e.g. move receipt read -> save as csv logic into ow…
• Save parsed html into eanProduct list
• Fine-tune ean product name & add quantity
• Rename 'product.dart' to 'receipt_product.dart'
• Add price to EANProduct & parse it from html
• Refactoring: define filePaths in main method
• Save eanProducts as csv & some refactoring
• Refactor 'product' -> 'receiptProduct'
• Move eanProduct csv generating into own file
• Refactor html to csv generating into own file