Update Python code formatting, configuration loading, and local model additions

1. Code Formatting:
   - Standardized Python code formatting across multiple files to align with PEP 8 guidelines. This includes adjustments to whitespace, line breaks, and inline comments.

2. Configuration Loader Enhancements:
   - Enhanced the `get_settings` function in `config_loader.py` to provide more robust handling of settings retrieval. Added detailed documentation to improve code maintainability and clarity.

3. Model Addition in __init__.py:
   - Added a new model "ollama/llama3" with a token limit to the MAX_TOKENS dictionary in `__init__.py` to support new AI capabilities and configurations.

pr_agent/cli.py

@@ -9,6 +9,7 @@ from pr_agent.log import setup_logger
 log_level = os.environ.get("LOG_LEVEL", "INFO")
 setup_logger(log_level)
 
+
 def set_parser():
     parser = argparse.ArgumentParser(description='AI based pull request analyzer', usage=
     """\
@@ -50,6 +51,7 @@ def set_parser():
     parser.add_argument('rest', nargs=argparse.REMAINDER, default=[])
     return parser
 
+
 def run_command(pr_url, command):
     # Preparing the command
     run_command_str = f"--pr_url={pr_url} {command.lstrip('/')}"
@@ -58,6 +60,7 @@ def run_command(pr_url, command):
     # Run the command. Feedback will appear in GitHub PR comments
     run(args=args)
 
+
 def run(inargs=None, args=None):
     parser = set_parser()
     if not args: