Shared uploads can't handle a non-existent _segments container

[sampsapenna]

Describe the bug

Current upload behavior is to break >5GiB files into segments as per Swift API guidelines. The process, however, currently expects that the segments should be pushed into a $CONTAINER_NAME_segments -container, which is a behavior similar to the native Openstack tools for object storage. The issue is, when a user has shared a container to the uploading party, the _segments container doesn't necessarily exist, thus leading to a situation where the upload runner creates a _segments container to the uploading project, instead of the _segments container being owned by the project that originally shared the container.

To Reproduce

Steps to reproduce the behaviour:

1. Open the UI
2. Create a container and share that to another project
3. Using the UI with another project, upload a file larger than 5GiB to the container shared to the project in the previous step
4. Observe the _segments container being present in the uploading project, instead of the project that originally created the container

Expected behavior

All object contents should at least be accessible to the project that originally shared the container, either by sharing the segments container to the project that owns this shared container, or by uploading the segments into the shared container.

Screenshots

Additional context