Sign Ubuntu Code of Conduct

In order to be able to distribute packages through a PPA, we need to sign the Code of Conduct using our GPG key: Login and follow https://launchpad.net/codeofconduct

Parent Task: #10407 (closed)

Original created by @u on 10413 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information