Blueprints-like editor for entities

[SNMetamorph]

Basically, relationships between different entities can be pretty good visualized with node graph. Entity can be represented as node with some inputs and outputs, and more detailed description for all these fields can be fetched from FGD file.

Moreover, there is good enough implementation of node graph UI for ImGui available: https://github.com/thedmd/imgui-node-editor
So, implementing such feature should be not that hard, I guess.