set LimitNOFILE for unit aqhome-data

currently we use one file per value, so we need a larger max number of
open files.

etc/aqhome-data.service

@@ -11,6 +11,7 @@ RemainAfterExit=no
 ExecStart=/usr/local/sbin/aqhome-data --datafolder=/var/lib/aqhome-data -p /var/run/aqhome-data.pid
 Restart=on-failure
 RestartSec=5s
+LimitNOFILE=16384
 
 [Install]
 WantedBy=multi-user.target