Implement `bundle` command
The idea for this API call came from @marcin. Here's the discussion: https://pad.isc.org/p/stork-cb-migration#L64
The overall long term goal is to have a command that could include multiple other commands and run them one after another as one change-set. Couple scenarios where this might be useful:
- changing subnet and all host reservations in it
- deleting subnet and all leases associated
- reservation migration from config file to database
This mechanism, if implemented correctly, will be very powerful.
One important feature of this new command is the ability to rollback changes if configurable number of errors is reached. It's important to acknowledge that full rollback in generic case is not possible, so this rollback should be limited to DB operations for now. We hope to expand the rollback in the future to maybe cover some other commands, but it will never be possible to rollback everything.
Since there are many ways how this could be implemented, I think the first step would be come up with a mini-design. Couple paragraphs in the ticket or on wiki should do the trick.