Move download all setting to config.py

downloader.py

@@ -1,6 +1,5 @@
 import html
 import logging
-import os
 import re
 import time
 from pathlib import Path
@@ -370,7 +369,7 @@ def download_all_invoices() -> list[Path]:
                 years = get_year_options(page)
                 if not years:
                     raise RuntimeError("No years found on billing page.")
-                download_all_years = os.getenv("DOWNLOAD_ALL_YEARS", "").lower() in ("1", "true", "yes", "y")
+                download_all_years = Config.DOWNLOAD_ALL_YEARS
                 if not download_all_years:
                     years = [years[0]]
                 logger.info("Group '%s' - years: %s", group["label"], years)