Feature Request: Stack Exchange metric "Time to First Response"

CHAOSS metric: [Time to First Response](https://chaoss.community/metric-time-to-first-response/)

In the context of Stack Exchange, it's not just any response, but specifically answers. (maybe the metric for SE should be called "Time to First Answer".

However, Time-to-answer might be hard because it implies that a response actually answers the question and doesn't pile on.

Therefore, I like the Time to First Response metric.

As a layman, I see in the `stackexchange` index:

- _id = (answer_id OR question_id)
- is_accepted_answer (same as is_accepted?)
- question_id (references the original _id (question_id) )
- type = answer/question
- creation_date

### Pseudo logic
```
IF question.question_id = answer.question_id AND answer.is_accepted_answer = TRUE
THEN
TIME-TO-ANSWER = difference between question.creation_date and answer.creation_date
```