Initial website using CppCMS

This adds a website that supports user account management, form uploads,
and dummy form processing.

I went with CppCMS so that I could manage everything within the freetron
application in different threads. That way after upload I can directly
add the item to a queue to be processed and monitor the result giving a
processing percentage to the user. Not there yet, but this is the first
step.
Added field for Key ID to website form

This better matches the current way this is handled in freetron,
rather than using the first form as the key.