Review delete directory operation

The delete directory operation needs to be reviewed.

Normally when a document is deleted, first a version of it is stored, so that the content is kept in case the delete was accidental.
We need to check whether this happens when a document is deleted through delete directory too.

Related to this, we need to ensure that `putObjectWithVersion` in https://github.com/adobe/da-admin/blob/main/src/storage/version/put.js rejects anything other than files.

Start by locating the delete directory operation and tracing whether it stores a document version before deletion. Then inspect src/storage/version/put.js and the putObjectWithVersion behavior for non-file inputs. Done means delete directory preserves recoverable document content and putObjectWithVersion rejects anything other than files.

Written by the indexing model from the issue text.