Promisification

[srnec]

• added new eslint rules & better configured existing eslint rules
• extracted OCR related logic into separate service class (can be reused in future for other restaurant parsers)
• added promise with timeout utility function (basically it adds the way to time out promises)
• extracted HTML scraping logic into its own service class (to extract logic into its own class and it will ease unit testing in future)
• promisification - getting rid of callbacks in favor of promises (mainly in MenuFetcher)
• refactored Config - it is no longer needed to instantiate it, it can be imported from anywhere

Next time I want to check for better options in debugging, watching (realtime reload) etc.