Add Mozilla Code of Conduct (#263)

* Add Mozilla Code of Conduct file

Fixes #262.

_(Message COC002)_

* Update CODE_OF_CONDUCT.md

Author: Mozilla-GitHub-Standards

CODE_OF_CONDUCT.md

@@ -0,0 +1,8 @@
+# Community Participation Guidelines
+
+This repository is governed by Mozilla's code of conduct and etiquette guidelines. 
+For more details, please read the
+[Mozilla Community Participation Guidelines](https://www.mozilla.org/about/governance/policies/participation/). 
+
+## How to Report
+For more information on how to report violations of the Community Participation Guidelines, please read our '[How to Report](https://www.mozilla.org/about/governance/policies/participation/reporting/)' page.