Bulk collection migration

[grb]

I’m re-opening the feature request for reasons explained below:

@grb

Re-opening this topic, because it does not seem possible to move items in bulk from one collection to another — the new bulk “Assign to collections” feature only copies items into the destination collections (with no ability to bulk remove the items from their original collections).

If I’m wrong about this, please demonstrate how to perform a bulk move. (@priya?)