Display elapsed time on issues from open-on-hold and open-resolved

It would be really helpful for us to get the amount of time between the following events:

• Open -> On-Hold
• Open -> Resolved

This will help to all of us to keep track of how much time we spend on an issue.

After those times are calculated you can add another column on https://bitbucket.org/[owner]/[repo]/issues called "Time spent" or something like that, showing the amount of time spent on each issue.