refactor(llm): rename LlmConfig to LLMConfig for consistency

Rename LlmConfig to LLMConfig across the codebase to follow consistent naming conventions.
Update all imports and usages to use the new name.
Update documentation and examples to reflect the change.

BREAKING CHANGE: LlmConfig has been renamed to LLMConfig. Users need to update their imports and usage.

tests/test_web_crawler.py

@@ -1,5 +1,5 @@
 import unittest, os
-from crawl4ai.async_configs import LlmConfig
+from crawl4ai.types import LLMConfig
 from crawl4ai.web_crawler import WebCrawler
 from crawl4ai.chunking_strategy import (
     RegexChunking,
@@ -43,7 +43,7 @@ class TestWebCrawler(unittest.TestCase):
             word_count_threshold=5,
             chunking_strategy=FixedLengthWordChunking(chunk_size=100),
             extraction_strategy=LLMExtractionStrategy(
-                llmConfig=LlmConfig(provider="openai/gpt-3.5-turbo", api_token=os.getenv("OPENAI_API_KEY"))
+                llm_config=LLMConfig(provider="openai/gpt-3.5-turbo", api_token=os.getenv("OPENAI_API_KEY"))
             ),
             bypass_cache=True,
         )