adding tree structure to layout inspector for NT subsection
adding tree structure to layout inspector for NT subsection

Summary: Added JSON parsing to make tree structure for NT subsection in layout inspector

Reviewed By: danielbuechele

Differential Revision: D12938117

fbshipit-source-id: 43967d2e970ff2ce7e9b2e05a99d58a95a71b650

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper