[Chore][Backend] Improve the scrapper code structure

[malparty]

Issue

The file scraper/internal/scraper/scraper.go handles many responsibilities including:

• Rotating the user agents
• Fetching the Google search requests (and building the URL)
• Parsing the HTML code
• Mapping the data to the model
• Defining the schema of the model

A similar issue is present in the file scraper/internal/server/server.go, which also contains code duplication between the BatchScrape and ScrapeResult functions.

Expected

To allow the application to grow while remaining clean and maintainable, the source code should be organized into sub-parts that correspond as much as possible to single responsibilities.

This also benefits testing in terms of clearly seeing "what should be tested, what should not".

[anhdt1911]

Thank you for your suggestion 🙇🏼‍♂️ .

I'll will separate scraper/internal/scraper/scraper.go into smaller reusable module and also remove the duplication of BatchScrape and BatchResult