refactoring

Summary:
This is refactoring the layout inspector. The old layout inspector was a single file with more than 1200 LOC which was really hard to debug and extend. This aims for splitting it up into smaller, easier to maintain components.

This version of the layout inspector only shows the view hierarchy for the regular view tree and the a11y tree. Additional features are added in stacked diffs.

Reviewed By: jknoxville

Differential Revision: D14100536

fbshipit-source-id: ca5e22dbb6ed9e34ce208a2a699ebfeb083904ad

src/index.js

@@ -14,6 +14,7 @@ export {
   FlipperPlugin,
   FlipperDevicePlugin,
 } from './plugin.js';
+export type {PluginClient} from './plugin.js';
 export {clipboard} from 'electron';
 export * from './fb-stubs/constants.js';
 export * from './utils/createPaste.js';