fix boxtools for rpi

- remove to_cm4
- create replace_in_file

router.py

@@ -9,7 +9,7 @@ from glob import glob
 from select import select
 from serial import serial_for_url
 from subprocess import Popen, PIPE, check_output, call, DEVNULL
-from utils import get_config
+from utils import BoxInfo
 
 FIREWALL_CONF = '/etc/nftables.conf'
 
@@ -478,6 +478,6 @@ class Service:
 
 
 if __name__ == '__main__':
-    routercfg = get_config('ROUTER')
+    routercfg = BoxInfo().read_config('ROUTER')
     if routercfg:
         Service.run(routercfg)