1 s mount delay

Add a 1 second mount delay (as in [crypto-scdard](https://github.com/Olf0/crypto-sdcard/blob/master/systemd/system/mount-cryptosd-luks%40.service#L19)).

Author: Olf0

systemd/system/mount-sd@.service

@@ -16,7 +16,7 @@ RemainAfterExit=yes
 # "udisksd" (per "udisks2.service") has finished starting, because
 # the udisks object for a partition has not been created yet, one
 # may give udisksd a second to settle:
-# ExecStartPre=/bin/sleep 1
+ExecStartPre=/bin/sleep 1
 ExecStart=/usr/bin/udisksctl-user mount -b /dev/%i
 ExecStop=/usr/bin/udisksctl-user unmount -b /dev/%i