Summary:
This diff moves the core of ElementsInspector to flipper-plugin and decouples it from legacy design system and Electron, without any significant improvements or API changes yet, which will follow later.
Colors and docs will be added later in this stack.
Reviewed By: passy
Differential Revision: D27660300
fbshipit-source-id: 96abfa3b3174fa852cf04ae119c23c3d629fee74