Update the multi-delete feature to use the batch delete functionality added in T395822: Catalyst work for multi-environment-deletion

The current way multi-delete functionality works is looping through the list of the demo wikis and sending individual DELETE API requests for each demo wiki.

In order to improve the efficiency of this functionality, we would like to combine multiple delete requests into a single Batch Delete request.

Please note that the BatchDelete API request is only available to wikis using Catalyst as their backend. The demo wikis running on the legacy virtual hosts do not support it.

AC

• If multiple demo wikis running on Catalyst are being deleted using multi-delete functionality, we should only send one Batch Delete API request
• If multiple demo wikis are being deleted using the multi delete functionality and some of them are running on the legacy virtual hosts, they should still be removed one by one