Ability to create Retrospectives Templates or Duplicate Existing ones

[tbraun1551]

Is your feature request related to a problem? Please describe. My team uses a new retro board for every retro. For our retro boards, we have a four columns.

1. Goals from last retro
2. What went well
3. What didn't go well
4. Future improvements

Ideally, we would be able to create new boards from a template or at least duplicate and reuse older boards. This way, the new columns to not need to be made by hand every time.

[FH-Inway]

Would love such functionality. This is similar to #504

[JStuve]

Resolved with #561