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/systemd_tty2_units/socat-smd11-from-ttyIN.service

@@ -0,0 +1,14 @@
+[Unit]
+Description=Read from /dev/ttyIN2 and write to smd11
+BindsTo=socat-smd11.service
+After=socat-smd11.service
+
+[Service]
+ExecStart=/bin/bash -c "/bin/cat /dev/ttyIN2 > /dev/smd11"
+ExecStartPost=/bin/sleep 2s
+StandardInput=tty-force
+Restart=always
+RestartSec=1s
+
+[Install]
+WantedBy=multi-user.target