Answer Overflow API integration #536

Is your feature request related to a problem? Please describe.
We are currently using https://www.answeroverflow.com/ to publicly show questions people asked and corresponding answers.
Unfortunately, resolved questions don't get marked as solved with Answer Overflow.

Describe the solution you'd like
When the original poster of a question closes their post with other users being thanked, the latest message of any of these thanked users is marked as the answer using this API endpoint: https://www.answeroverflow.com/docs/api-reference/messages/update-solution-for-a-message

The necessary API key should be added to the systems config.

Describe alternatives you've considered

• Let users mark posts as an answer using Answer Overflow. This introduces an additional burden on users and most users would probably not do that.