SW360 Updater: Handle change status

[neubs-bsi]

Summary of the Feature

In the SW360 data model the variable "change status" is supposed to reflect weither a component release should update an existing release or contains changed data (for example different, curated sources), thus requiring to be stored as an own release with an appendix, as described in the data model documentation.

This functionality is still missing.

Idea:

• change status is CHANGED
• release is not updated with different information, but instead createRelease is called and a new release with a version and an appendix (e.g. 1.0.0-modified) is created.

Acceptance Criteria

• Change Status reflects storage behaviour
• A way of handling a 2nd modified release (e.g. release 1.0.0_modified already exists and the change status is once more "CHANGED") is introduced and defined
• Documentation is updated

Definition of Done

• Acceptance criteria fulfilled
• A PR is created, the CI infrastructure reports green
• The PR is reviewed and approved
• No TODOs left in the code unless explained in the ticket, if something else is still open, this is summarized in a comment in the issue
• Test cases are created to prove the functionality of the feature
• Documentation is updated