Management API for dynamic root and query steps. (#15505)

* Added management API for dynamic root and query steps.

* Open API

* Split models, use required and rename a little

* Rename query steps

* Make request culture and segment optional

* Introduce explicit back-office variation context

* Simplify query endpoint path

* Correct field naming

* Updated OpenApi.json

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

src/Umbraco.Core/DynamicRoot/QuerySteps/IDynamicRootQueryStep.cs

@@ -5,4 +5,5 @@ namespace Umbraco.Cms.Core.DynamicRoot.QuerySteps;
 public interface IDynamicRootQueryStep
 {
     Task<Attempt<ICollection<Guid>>> ExecuteAsync(ICollection<Guid> origins, DynamicRootQueryStep filter);
+    string SupportedDirectionAlias { get; }
 }