Delete forked repos after Batch Change is completed

[marcleblanc2]

Feature request description

We would like the option to delete all the repository forks created for a batch change once it’s completed or deleted.

Is your feature request related to a problem? If so, please describe.

Repo management / code host hygiene, end up with forks of many repos not needed after the Batch Change is completed.

Describe alternatives you've considered.

Deleting these repos manually. Not efficient, especially with many repos.

Additional context

Requested by customer https://github.com/sourcegraph/accounts/issues/569 in support ticket https://sourcegraph.zendesk.com/agent/tickets/13434

[marcleblanc2]

Related: https://github.com/sourcegraph/sourcegraph/issues/50354 https://github.com/sourcegraph/sourcegraph/issues/23471