fix: creates `drafts` property only at entities that are truly draft enabled

[stockbal]

Uses a new approach taken from @sap/cds-compiler/lib/transform/draft.js#generateDraft to detect draft enabled entities.

In essence there are only 2 cases when a draft table will be generated for an entity and therefore the .drafts property of an entity will return a valid CSN entity reference during runtime.

1. Entity A is exposed in a service and has the annotation @odata.draft.enabled

2. Entity B is used as composition in Entity A or an Entity (C-Z) that is a composition of Entity A

   // model.cds
   entity A { b : Composition of B }
   entity B { c : Composition of C }
   entity C { d: Composition of D }
   entity D { }
   
   // service.cds
   serivce Service {
     @odata.draft.enabled
     entity P1 as projection on A;
   }
   

   • Service.P1 is draft enabled via annotation
   • Service.B, Service.C and Service.D are draft enabled via composition relationship
   • A, B, C, D remain as is and won't have access to a .drafts property

Further remarks

• The refactoring uses the inferred csn model, because the xtended one does not include the autoexposed entities.
• The draft state is no longer propagated top-down, as the model entities must not get the drafts properties. Instead, all draft enabled service-entities are collected in an array

Fixes #68