Notebook to compute stats about time to respond on issue

[jlewi]

@hamelsmu I were discussing how we could eventually show the impact of auto-labeling issues.

One goal of efficiently triaging and routing issues is to reduce the time before someone responds to the issue.

We'd like a notebook to measure response time. Response time would be the time from when the issue is created until someone other than the creator responds to it; a response could be

• A comment
• Labeling the issue
• Assigning the issue to someone
• Closing the issue