Build support for Java apps

[chgeo]

Is your feature request related to a problem? Please describe.
For Java apps that use the cap-java/cds-feature-attachments plugin, users have to manually add UI annotations for attachments:

annotate service.Incidents with @(
  UI.Facets: [
    ...,
    {
      $Type  : 'UI.ReferenceFacet',
      ID     : 'AttachmentsFacet',
      Label  : '{i18n>attachments}',
      Target : 'attachments/@UI.LineItem'
    }
  ]
);

Describe the solution you'd like
The cap-js/attachments plugin has automated the UI annotation creation for Node.js apps. The request is to allow the same code to run in the build for Java apps.

Other plugins follow the same approach, where a JS plugin offers the build support for Java apps.

[github-actions]

👋 Hello @chgeo, thank you for submitting this issue. Our team is reviewing your report and will follow up with you as soon as possible.

[chgeo]

@Schmarvinius this is what we discussed at reCAP.
@beckermarc FYI