softethervpn: added new package 4.21-9613

- based on the work done by el1n with his authorization (https://github.com/el1n/OpenWRT-package-softether)
- updated softethervpn to latest version
- introduced necessary patches for lede compatibility (nossl3)

Signed-Off-by: Federico Di Marco <fededim@gmail.com>

net/softethervpn/files/vpnclient.init

@@ -0,0 +1,12 @@
+#!/bin/sh /etc/rc.common
+START=60
+
+start(){
+        logger -t 'softethervpn' "Starting softether vpnclient service."
+	/usr/bin/env LANG=en_US.UTF-8 /usr/libexec/softethervpn/vpnclient start
+}
+
+stop(){
+        logger -t 'softethervpn' "Stopping softether vpnclient service."
+	/usr/bin/env LANG=en_US.UTF-8 /usr/libexec/softethervpn/vpnclient stop
+}