Adds some settings to check flipper-server state

Summary:
There's one setting: to enable or disable flipper-server.

However, I've added some current running state to it. If there's a better way of doing this, please do let me know.

Reviewed By: aigoncharov

Differential Revision: D37276670

fbshipit-source-id: f6c941cf0cfe55c267b9bcb9f799934fba1e28ef

desktop/flipper-server-core/src/utils/settings.tsx

@@ -69,6 +69,9 @@ function getDefaultSettings(): Settings {
     enablePluginMarketplace: false,
     marketplaceURL: '',
     enablePluginMarketplaceAutoUpdate: true,
+    server: {
+      enabled: false,
+    },
   };
 }