Community Guidelines - fixes https://github.com/HabitRPG/habitrpg/issues/3801

Must be merged at the same time as https://github.com/HabitRPG/habitrpg/pull/4033

Required to create a Community Guidelines document as described in https://github.com/HabitRPG/habitrpg/issues/3801

Sorry about the irrelevant commits in the history. Will they cause problems? If so I can create a new branch and patch it from this one. The file changes here are all correct.