Add merge feature for Change Set deliveries which includes modification of attribute and artifact type properties to prevent destructive behaviour

Problem

The change set in the source stream contains adding an attribute to an artifact type. While delivering the change, the artifact type configuration of the target child stream is overwritten and stream specific attributes are disconnected from artifact type.

Steps to reproduce

1. Create a change set on source stream that includes adding an already existing attribute to an already existing artifact type.

2. Deliver this change set to the target stream

3. Obeserve overwritten artifact type configuration of target stream and disconnection of target stream specific attributes from artifact type that were associated before CS delivery.

Solution

Add feature with options on how to proceed with attribute and artifact type updates while delivering.

Why is it useful

With this feature deliveries won´t be (worst case unknowingly) destructive for target streams.

Who would benefit from it

DNG users that uses Change set deliveries btw. streams to propagate changes and knowingly/unknowingly includes association of attributes to artifact types.

How should it work
Display of updated artifact type and following options to proceed:
1.override target artifact type properties with source artifact type properties --> target stream specific attributes will be disconnected from artifact type if they are not the same as the attributes associated to the artifact type properties of source stream (current automatic behavior)
2.merge target artifact type properties with source artifact type properties --> target stream specific attributes will be added to the attributes already associated to the artifact type properties of source stream
3.keep target artifact type properties as is --> target stream specific attributes remain associated to the artifact type as they were before change set delivery