storage-users high memory usage when S3ng multipart uploads are enabled

_Originally posted by @butonic in https://github.com/owncloud/ocis/issues/8589#issuecomment-2263106849_

> so now I see the storageusers pods being OOM killed as described in https://github.com/owncloud/ocis/pull/9656#issuecomment-2252750226
>
> I currently think we are running into https://github.com/kubernetes/kubernetes/issues/43916#issuecomment-2249191975
>
> edit: @wkloucek pointed out that we have to disable mime multipart uploads because it allocates too much memory

Start with the storage-users S3ng multipart-upload path and the context in PR 9656; compare the OOM behavior with Kubernetes issue 43916. Locate where MIME multipart uploads are enabled and verify that disabling them prevents storage-users pods from being OOM killed.

Written by the indexing model from the issue text.