doc: Add Code of Conduct

We'll use the CNCF Code of Conduct as it is well written, well-known an
appropriate for Cilium. Adjustments have been made to point to Cilium
community specific contact details.

Signed-off-by: Thomas Graf <[email protected]>

CODE_OF_CONDUCT.md

@@ -0,0 +1,46 @@
+## Community Code of Conduct v1.0
+
+This is Code of Conduct is based on the [CNCF Code of
+Conduct](https://github.com/cncf/foundation/edit/master/code-of-conduct.md).
+See the referred document for translated versions into different languages. The
+text below is modified with Cilium community specific contact details.
+
+### Contributor Code of Conduct
+
+As contributors and maintainers of this project, and in the interest of fostering
+an open and welcoming community, we pledge to respect all people who contribute
+through reporting issues, posting feature requests, updating documentation,
+submitting pull requests or patches, and other activities.
+
+We are committed to making participation in this project a harassment-free experience for
+everyone, regardless of level of experience, gender, gender identity and expression,
+sexual orientation, disability, personal appearance, body size, race, ethnicity, age,
+religion, or nationality.
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery
+* Personal attacks
+* Trolling or insulting/derogatory comments
+* Public or private harassment
+* Publishing others' private information, such as physical or electronic addresses,
+ without explicit permission
+* Other unethical or unprofessional conduct.
+
+Project maintainers have the right and responsibility to remove, edit, or reject
+comments, commits, code, wiki edits, issues, and other contributions that are not
+aligned to this Code of Conduct. By adopting this Code of Conduct, project maintainers
+commit themselves to fairly and consistently applying these principles to every aspect
+of managing this project. Project maintainers who do not follow or enforce the Code of
+Conduct may be permanently removed from the project team.
+
+This code of conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community.
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project maintainers or our mediator, Beatriz
+Martinez <[email protected]>.
+
+This Code of Conduct is adapted from the Contributor Covenant
+(http://contributor-covenant.org), version 1.2.0, available at
+http://contributor-covenant.org/version/1/2/0/