Summary:
1. Remove fs.readFile from some plugins
2. Add "importFile" to FlipperLib and RenderHost
See D32492149 for context
Followups:
1. Decapitate Stella's sendToPhone
2. Decapitate crash reporter
3. Figure out how to approach navigation
4. Figure out how to approach FileSelector
Reviewed By: mweststrate
Differential Revision: D32496775
fbshipit-source-id: e150aa56a2c2c1eb12a4c03c801f76cd76485a9d
a279b9bc43