Track server start

Summary:
Need to answer:

- How many starts a day over time

Reviewed By: antonk52

Differential Revision: D46219995

fbshipit-source-id: bffaeadf684a2d34c6e145784c5a86dbaf5f532a

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

@@ -224,8 +224,10 @@ async function startProxyServer(
       return new Promise((resolve) => {
         proxyServer?.listen(config.port);
         server.listen(socketPath, undefined, () => resolve());
-
-        // TODO: track server has started at this stage.
+        tracker.track('server-started', {
+          port: config.port,
+          tcp: config.tcp,
+        });
       });
     };
     resolve({app, server, socket, readyForIncomingConnections});

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

@@ -10,6 +10,7 @@
 import {getLogger} from 'flipper-common';
 
 type TrackerEvents = {
+  'server-started': {port: number; tcp: boolean};
   'server-auth-token-verification': {
     successful: boolean;
     present: boolean;