Adding save to HF support for async webcrawler

[AndreaFrancis]

This pull request addresses #257. It introduces a persistence strategy layer to the project, allowing for more flexible data storage options.

Key changes:

• Added an abstract DataPersistenceStrategy class for defining various persistence strategies.
• Implemented HFDataPersistenceStrategy, a concrete strategy for pushing data to a Hugging Face dataset.
  With this update, data extracted via the crawl process can now be seamlessly uploaded to the Hugging Face Hub as datasets, enhancing data sharing and accessibility.
  Once this PR is adopted by the community, it will be easy to filter all datasets created using the crawl4ai library by visiting https://huggingface.co/datasets?other=crawl4ai

[unclecode]

@AndreaFrancis A supernova thanks to your pull request! What excites me most is how beautifully it aligns with the library's design philosophy. Amazing work! I’ll review it soon, run some tests, and it’ll be my pleasure to merge it. I’d love to invite you to our Discord, please share your email, and I’ll send over the invitation link.

[AndreaFrancis]

@unclecode Thank you for the kind words! 😊 I’m glad the pull request aligns with the library’s design. Looking forward to your feedback!
Joining Discord sounds great, here’s my email: [email protected]
Thanks again for the invitation! 🌟

[unclecode]

@AndreaFrancis You are very welcome, looking forward to having talented developers and data scientists like yourself in the Crawl4ai community; we work together and form the no. 1 data extraction open source library in favor of data liberty. I will send the invitation link.