feat: add a Contributor Covenant Code of Conduct

[bufferoverflow]

Based on https://www.contributor-covenant.org/version/2/1/code_of_conduct/code_of_conduct.md , [INSERT CONTACT METHOD] has been replaced by [email protected].

[fmoessbauer]

Hi @bufferoverflow , thanks for bringing this up. As discussed internally, I prefer to have the CoC on the GitHub Siemens OU (if possible), instead of having one per project. By that we can keep things consistent across all our repos. @jan-kiszka WDYT?

[bufferoverflow]

@fmoessbauer I agree having it at org level is much better. I was not aware that this is possible.

[jan-kiszka]

Org-level, and projects can override it, just like with the security.md? That would be useful. We need to make sure "inventing" CoC for projects that already have one, e.g. for upstream forks like Linux.

[nejch]

Org-level, and projects can override it, just like with the security.md? That would be useful. We need to make sure "inventing" CoC for projects that already have one, e.g. for upstream forks like Linux.

@jan-kiszka we copied the approach from the security policy, so yes we have a little Scope section where we mention this (exclude forks and projects with existing CoC). See siemens/.github#17

[fmoessbauer]

Closing in favor of siemens/.github#17. Anyways, thanks for bringing this up.