xray-core: increase nofile limitation

This fixes "too many open files" error caused by max-file limitation
when xray processes large traffic.

Reported-by: Terry Ding <terryding77@gmail.com>
Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>
(cherry picked from commit d98fd52865)

net/xray-core/files/xray.init

@@ -39,6 +39,8 @@ start_service() {
 	procd_set_param env XRAY_LOCATION_ASSET="$datadir"
 	procd_set_param file $conffiles
 
+	procd_set_param limits core="unlimited"
+	procd_set_param limits nofile="1000000 1000000"
 	procd_set_param stdout 1
 	procd_set_param stderr 1
 	procd_set_param respawn