Add postrm script to kill the mozillavpn instances when the linux package is uninstalled - fixes VPN-2048 (#3304)

Author: bakulf

linux/debian/mozillavpn.postrm

@@ -0,0 +1,7 @@
+#!/bin/sh
+case "$1" in
+remove)
+  killall -q mozillavpn || true
+  ;;
+esac
+exit 0