This follows up on DBZ-4393; the following tasks remain as per the original PR:

• Agree on the descriptor design (do we truly need two classes, see question inline); decision: will pull up everything into one flat contract
• Apply the plug-in to all connector modules
• Make sure the generated descriptors are added to the connector archives (see assembly.xml)
• Update Debezium UI to obtain the API specs from the connector archives (UI backend done, UI frontend to be done via DBZ-4619)
• Create downstream format (to be done via MGDCTRS-109)
• Harmonize upstream and downstream formats as much as possible (to be done vai DBZ-4620)