remove intro
remove intro

Summary: Removing the Intro component. It's not used anywhere and wasn't even exported from the flipper package.

Reviewed By: passy

Differential Revision: D16807181

fbshipit-source-id: 87d4b92e275a364e478a6999a144eb66e3977c66

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