Draft: wip: add total capacity spent on group over time period

Add new command to show effort expended on a project, based on estimations.

For example, this has been used to calculate how much time was spent on activate account/get-your-account by the IAM team.

Wilson team mean iteration capacity last 38 weeks: 16.236842105263158 (exiting command)

Wilson total over last 38 weeks in all of /uis/devops groups: 308.5

Wilson total over last 38 weeks in /uis/devops/iam : 280.0

Wilson total over last 38 weeks in Account Activate /uis/devops/iam/activate-account Total: 139.5 (last 32/38 weeks) 

Approx 8-10 sprints spent on /uis/devops/iam/activate-account over the course of 32 weeks.