az boards - copying capacity from last sprint programmatically

**Related command**
az boards

**Is your feature request related to a problem? Please describe.**
I'm able to programmatically create sprints and pre-allocate hours to work items indefinitely, but there isn't a way via "az boards" to allocate the work hour capacity for all individuals on my team. We have to go in and select "copy from last sprint" each time.

**Describe the solution you'd like**
It would be nice for an extension of "az boards" to have a "capacity" feature for copying from last sprint. I know there's an "az capacity" but it seems like having "az boards capacity" is a discrete method in your code.

**Describe alternatives you've considered**
Someone has been going in every two weeks and copying our sprint capacity manually from the last sprint. The only part we can't script out is the capacity, so we'd be excited to see that feature.