V14: Composition endpoints for Document and Media types (#15584)

* Adding response/request models

* Adding mapping

* Adding factory

* Adding controllers

* Moved to correct (generic domain) namespace

* Renamed to reflect the correct domain + renamed IsAllowed to IsCompatible

* Renaming + TODO

* Removed presentation logic + TODO

* Fixed controller

* Attempt for generic implementation

* Enable composition of media types + refactor content/media type editing tests to prove it (and a little renaming of a mis-named property)

* Remove unused classes

* Introducing GetAvailableCompositionsAsync to EditingServices

* Implement GetAvailableCompositionsAsync

* Base share implementation

* Tests

* Tests

* Renaming

* Clean up controller

* Clean up test

* Remove redundant check

* Create and use generic models

* Add shared implementation

* Fix and rename doc type mapper

* Fix document Type factory

* Add missing response type

* Create a base request model

* Make key nullable when new item

* Media type response models

* Default isElement to false and remove isElement param from media type related things

* Create mappings for media type compositions

* Inject generic base service to reuse implementation amongst concrete services

* Add new composition endpoints for media type

* Use specific type

* Add a reference comment to other test suite

* Add more test cases

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Co-authored-by: kjac <kja@umbraco.dk>

src/Umbraco.Core/Models/ContentTypeEditing/MediaTypeCreateModel.cs

@@ -4,5 +4,5 @@ public class MediaTypeCreateModel : MediaTypeModelBase
 {
     public Guid? Key { get; set; }
 
-    public Guid? ParentKey { get; set; }
+    public Guid? ContainerKey { get; set; }
 }