Add new files for 2nd Socat bridge

-Create a new set of systemd units to chose from for the creation of ttyIN2 and ttyOUT2 for a 2nd separate AT channel
-Create a new script that kills the smd7 port bridge when smd7 is needed for use by ttyOUT or ttyOUT2

socat-at-bridge/killsmd7bridge

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+# Look for the process by its command and kill it so socat can have smd7 instead
+pkill -f "/usr/bin/port_bridge smd7 at_usb2 1"