Add Creative Commons License to resources/non-commercial (#1284)

## Description:
Add a Create Commons non commercial license to resources/non-commercial
directory.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:
evan

README.md

@@ -17,10 +17,11 @@ This is a fork/rewrite of WarFront.io. Credit to https://github.com/WarFrontIO.
 
 # OpenFront - Licensing
 
-This project uses a dual-licensing approach:
+This project uses a multi-licensing approach:
 
 - Code in the `server/` and `core/` directory is licensed under MIT
 - Client code (in the `client/` directory) is licensed under GPL v3
+- Assets in resources/non-commercial are under CC BY-NC 4.0 with OpenFront LLC Commercial Exemption. By contributing assets to /non-commercial/, contributors agree that OpenFront LLC may use their contributions for commercial purposes while the contributions remain CC BY-NC 4.0 for all other parties.
 
 See LICENSE file for more details.