refactor(agents): organise the agents package by what each module holds

- tools.py: the analysts' data tools, previously seven modules under utils
- context.py (was agent_utils, without its tool re-exports), state.py, rating.py and structured.py sit beside schemas.py
- every role package has an __init__

tests/test_news_analyst_prompt.py

@@ -8,7 +8,7 @@ import inspect
 import pytest
 
 import tradingagents.agents.analysts.news_analyst as na
-from tradingagents.agents.utils.news_data_tools import get_news
+from tradingagents.agents.tools import get_news
 
 
 @pytest.mark.unit