Enhance Crawl4AI with new features and documentation

- Fix crawler text mode for improved performance; cover missing `srcset` and `data_srcset` attributes in image tags.
  - Introduced Managed Browsers for enhanced crawling experience.
  - Updated documentation for clearer navigation on configuration.
  - Changed 'text_only' to 'text_mode' in configuration and methods.
  - Improved performance and relevance in content filtering strategies.

docs/md_v2/blog/releases/0.4.1.md

@@ -37,11 +37,11 @@ Here’s how to turn it on:
 
 ```python
 crawler = AsyncPlaywrightCrawlerStrategy(
-    text_only=True  # Set this to True to enable text-only crawling
+    text_mode=True  # Set this to True to enable text-only crawling
 )
 ```
 
-When `text_only=True`, the crawler automatically:
+When `text_mode=True`, the crawler automatically:
 - Disables GPU processing.
 - Blocks image and JavaScript resources.
 - Reduces the viewport size to 800x600 (you can override this with `viewport_width` and `viewport_height`).