Prepare applet code for headless enviroment
The chunk size is now 512KB, adds server notification

After all the chunks have been successfully uploaded, we notify
the server to combine the chunks, extract the content and upload it
to S3
Expose the surveyUploadUrl in the FLOW.Env object
Initial implementation of combine/extract/upload process

* Needs to be re-implemented using a Quartz job to get the
  benefit the running threads in the scheduler