Issues with upload for 1:1

[dereuromark]

The behavior, when attached for uploading, should create additional *Tmp relations.
Those would be used for uploading then.
This way they wont intersect with the existing image on the entity property and cause partial overwrite or strange side effects.
Once fully uploaded the auto-perge (if enabled) kicks in and there is only 1 image in this case still after redirect.

[burzum]

Can you provide an isolated PR with test coverage for this feature and make it optional, means being able to enable and disable it on the behavior? I'll accept such a PR and solution.