Expose info endpoint

Summary:
Expose an endpoint to retrieve server environment information.

We can use version information and process number to aid engineers with troubleshooting Flipper.

Reviewed By: antonk52

Differential Revision: D49537325

fbshipit-source-id: 511fe4441638f91cd35f13706ceeeb515051416b

desktop/app/src/init.tsx

@@ -154,11 +154,14 @@ async function getFlipperServer(
 
   console.info('[flipper-server] Not running/listening, start');
 
-  const {readyForIncomingConnections} = await startServer({
-    staticPath,
-    entry: 'index.web.dev.html',
-    port,
-  });
+  const {readyForIncomingConnections} = await startServer(
+    {
+      staticPath,
+      entry: 'index.web.dev.html',
+      port,
+    },
+    environmentInfo,
+  );
 
   const server = await startFlipperServer(
     appPath,