UE-18498 HLOD: Add functionality for choosing appropriate LOD from source StaticMesh when creating HLOD meshes
Fix for empty LOD actor not getting removed
Added context menu entry to remove SMA node from cluster and exclude from cluster generation in the future (setting the Auto LODGeneration flag on the actor to true)
Added feedback to Outliner when a Cluster contains less actors than the value of ôMin Number of Actors to buildö for the HLOD level it is in
Added option to create HLOD volume containing the selected clusters actors, for persistent changes in clustering generation
Added experimental slider for forcing the view Hierarchical LOD level
[CL 2665844 by Jurre deBaare in Main branch]