feat: config directory as argument

src/netcup_dns/main.py

@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 import configparser
 import ipaddress
+import sys
 from functools import lru_cache
 from pathlib import Path
 
@@ -13,7 +14,11 @@ def main():
     """
     The main effort is done by https://github.com/nbuchwitz/nc_dnsapi
     """
-    cfg_dir = Path('cfg')
+    if len(sys.argv) > 1:
+        cfg_dir = Path(sys.argv[1])
+    else:
+        cfg_dir = Path('/etc/netcup-dns')
+
     if not cfg_dir.exists():
         raise Exception(f'The config directory is missing: {cfg_dir}')