Copy over dart container and add to jenkinsfile

dart/entrypoint.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+cd /home/container
+
+# Make internal Docker IP address available to processes
+INTERNAL_IP=$(ip route get 1 | awk '{print $(NF-2);exit}')
+export INTERNAL_IP
+
+# Print Dart version
+dart --version
+
+# Replace startup variables
+MODIFIED_STARTUP=$(echo -e ${STARTUP} | sed -e 's/{{/${/g' -e 's/}}/}/g')
+echo ":/home/container$ ${MODIFIED_STARTUP}"
+
+# Run the server
+eval ${MODIFIED_STARTUP}