feat(crawler): add network request and console message capturing

Implement comprehensive network request and console message capturing functionality:
- Add capture_network_requests and capture_console_messages config parameters
- Add network_requests and console_messages fields to models
- Implement Playwright event listeners to capture requests, responses, and console output
- Create detailed documentation and examples
- Add comprehensive tests

This feature enables deep visibility into web page activity for debugging,
security analysis, performance profiling, and API discovery in web applications.

tests/general/test_crawlers.py

@@ -0,0 +1,17 @@
+
+# example_usageexample_usageexample_usage# example_usage.py
+import asyncio
+from crawl4ai.crawlers import get_crawler
+
+async def main():
+    # Get the registered crawler
+    example_crawler = get_crawler("example_site.content")
+    
+    # Crawl example.com
+    result = await example_crawler(url="https://example.com")
+        
+    print(result)
+            
+
+if __name__ == "__main__":
+    asyncio.run(main())