Create entrypoint.sh for application startup

Add entrypoint script to configure and run the application.

entrypoint.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+set -eu
+
+ARGS=""
+
+# Required args (-s and -d)
+ARGS="$ARGS -s ${SERVER_ADDR}"
+ARGS="$ARGS -d ${DEVICE_ADDR}"
+
+# Optional forwarding listener (-f) and sqlite (-sql)
+if [ "${ENABLE_FORWARD}" = "true" ]; then
+  ARGS="$ARGS -f ${FORWARD_ADDR}"
+fi
+
+if [ "${SQLITE}" = "true" ]; then
+  # Put DB in mounted volume; your script uses sqlite_file = 'meshcore_multitcp.db'
+  # so we run from /data to keep it persistent.
+  cd /data
+  ARGS="$ARGS -sql"
+else
+  cd /app
+fi
+
+# Logging controls (-q or -v). Default is info (no flag).
+if [ "${LOG_LEVEL}" = "quiet" ]; then
+  ARGS="$ARGS -q"
+elif [ "${LOG_LEVEL}" = "debug" ]; then
+  ARGS="$ARGS -v"
+fi
+
+exec python3 /app/meshcore_multitcp.py $ARGS