Aleksi Hietanen
efa7f5a4d0
Refactor common methods in in-memory data providers (#9308)
* Refactor common methods of InMemoryHierarchicalDataProvider and ListDataProvider to a single interface
* Rename HierarchyData and InMemoryHierarchicalDataProvider, introduce HasHierarchicalDataProvider
* Additionally adds a helper method for recursive constructing
TreeData with a child item provider.