Move files to flipper-common

Summary: Moved Logger, sleep, timeout and server contract types to flipper-common packages.

Reviewed By: passy

Differential Revision: D31475790

fbshipit-source-id: 42d2147698875f9e919ad5250f9953f3bff3ec2d

desktop/flipper-common/src/index.tsx

@@ -7,6 +7,12 @@
  * @format
  */
 
-export function helloWorld() {
-  return true;
-}
+export {
+  Logger,
+  LoggerTrackType,
+  LoggerTypes,
+  LoggerArgs,
+} from './fb-interfaces/Logger';
+export * from './server-types';
+export {sleep} from './utils/sleep';
+export {timeout} from './utils/timeout';