prepare HARDENS project for public release

[kiniry]

Now that the project has concluded, we can release HARDENS to the public.

We have a bit of polishing to do before we can do so. Here are the necessary subtasks:

• [x] add or update LICENSE.txt files for all sub-units
• [x] add Copyright and licensing notices to appropriate files
• [x] add NRC required disclaimer to slide presentations and report