S3 objects not cleaned up on transaction failure

[keirafadams]

Describe the bug

Currently, a failed VDMS transaction will not lead to the associated image being removed, causing a storage leak.

To Reproduce

Add multiple images, include an invalid operation (or garbage data) that will trigger a failure on the second (or later) image add.

Expected behavior

If a transaction fails, the S3 objects should be removed as well.

Additional context

We need to have a broader discussion on VDMS transactions vs individual query transactions, because when we start including things like remote storage it gets very messy.

[cwlacewe]

Closed by #306