[DF-2636] Moved dropping material to MaterialsDropSystem
Merge branch 'feature-integration-new-materials' of https://github.com/dava/dava.framework into feature-integration-new-materials
[DF-2636] Added drag & drop to entity with several materials
[DF-2636] Added function to switch materials
Merge branch 'feature-integration-new-materials' of https://github.com/dava/dava.framework into feature-integration-new-materials