Move Tail to flipper-server-core

Summary: Tail is a server-side logging utility. We cannot add it to flipper-frontend-core as it is going to be included into the browser bundle then and break the build.

Reviewed By: antonk52

Differential Revision: D36771864

fbshipit-source-id: 169cdb88543f1e47f39e8c0976c3a3f45c0439d5

desktop/flipper-server-core/src/index.tsx

@@ -12,6 +12,7 @@ export {loadSettings} from './utils/settings';
 export {loadLauncherSettings} from './utils/launcherSettings';
 export {loadProcessConfig} from './utils/processConfig';
 export {getEnvironmentInfo} from './utils/environmentInfo';
+export * from './utils/tail';
 
 import GKImplementation from './fb-stubs/GK';
 export {setupPrefetcher} from './fb-stubs/Prefetcher';