Model mapping PoC (#15546)

* First take at new models for improved mapping between client and server

* Add variants to Media

* Re-introduced lost names

* Start breaking apart "Id" reference properties in request models as well

* Refactor to fix OpenAPI spec

* Discard TODO (not relevant)

* Split recycle bin response models

* Delete unused marker interface

* Use reference properties for content and media type handling

* Rework document and media types to be explicit in relations (do not expose "content type", it is an implementation detail)

* Mapping for document and media type copy + move

* Ensure correct response model for Media

* Regenerate OpenAPI JSON after forward merge

* Fix forward merge issues

* Fix forward merge + regenerate OpenApi.json

* Added unit tests for content state helper

* Move "allowed document types" endpoint to document type silo, refactored services and added "allowed media types"

* Regenerate OpenApi.json after forward merge

* Do not include content state for media items

* Review fix

src/Umbraco.Cms.Api.Management/ViewModels/User/Current/CurrentUserResponseModel.cs

@@ -1,6 +1,6 @@
 namespace Umbraco.Cms.Api.Management.ViewModels.User.Current;
 
-public class CurrentUserResponseModel : INamedEntityPresentationModel
+public class CurrentUserResponseModel
 {
     public required Guid Id { get; init; }
 

src/Umbraco.Cms.Api.Management/ViewModels/User/Item/UserItemResponseModel.cs

@@ -2,6 +2,6 @@
 
 namespace Umbraco.Cms.Api.Management.ViewModels.User.Item;
 
-public class UserItemResponseModel : ItemResponseModelBase
+public class UserItemResponseModel : NamedItemResponseModelBase
 {
 }

src/Umbraco.Cms.Api.Management/ViewModels/User/UserResponseModel.cs

@@ -2,7 +2,7 @@
 
 namespace Umbraco.Cms.Api.Management.ViewModels.User;
 
-public class UserResponseModel : UserPresentationBase, INamedEntityPresentationModel
+public class UserResponseModel : UserPresentationBase
 {
     public Guid Id { get; set; }