Create Code of Conduct Page

[shushugah]

While every single event will have the Code of Conduct included in the bottom. A stand alone page should exist with the full text of the Code of Conduct, and contact info of CoC Committee members. https://berlincodeofconduct.org/ and it should ALSO be shown in the header navigations

• the url is /code-of-conduct
• code-of-conduct.markdown file is created with appropriate text
• it shows up in the header (next to About, Events)