Have a process for responding to Code of Conduct reports

Related to https://github.com/mozilla/diversity/blob/master/evaluation_tools/governance-basic.md after making clear who will receive these reports, we should document a process for responding to them.

Probably such reports should be sent to everyone from tails@, except to the person(s) that this report involves if any and then discussed internally.

Parent Task: #16783

Original created by @u on 16814 (Redmine)

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