[settings] fuck it, rework the settings again

this time using pydantic-settings as a base
- removed all os.getenv calls
- removed the secret_key default option
- reworked database loading, creating tables
- prob. something else also but its 4:30 and i have to sleep

test/test_services/test_database.py

@@ -9,10 +9,10 @@ def test_create_db_and_tables():
     # This is primarily an integration test
     from sqlalchemy import inspect
 
-    from app.services.database import engine
+    from app.services.database import get_engine
 
     create_db_and_tables()
-    inspector = inspect(engine)
+    inspector = inspect(get_engine())
 
     # Check that tables exist
     tables = inspector.get_table_names()