add openai model to config, rework logging to use appdirs logging dir

src/backend/thread_bookgrabber.py

@@ -5,11 +5,11 @@ from src.backend import Database
 from src.logic.webrequest import BibTextTransformer, WebRequest
 import loguru
 import sys
-
+from src import LOG_DIR
 log = loguru.logger
 log.remove()
 log.add(sys.stdout, level="INFO")
-log.add("logs/application.log", rotation="1 MB", retention="10 days")
+log.add(f"{LOG_DIR}/application.log", rotation="1 MB", retention="10 days")
 
 
 # logger.add(sys.stderr, format="{time} {level} {message}", level="INFO")