Move config file exceptions into app.exceptions

Move ConfigDirError, ConfigFileNotFoundError, ConfigFileExistsError, ConfigFileWriteError, and ConfigFileNameError from raw_config_io_service into the shared domain exception module. Update router and tests to import the exceptions from app.exceptions.

backend/app/routers/file_config.py

@@ -52,7 +52,7 @@ from app.models.file_config import (
     JailConfigFilesResponse,
 )
 from app.services import raw_config_io_service
-from app.services.raw_config_io_service import (
+from app.exceptions import (
     ConfigDirError,
     ConfigFileExistsError,
     ConfigFileNameError,