Copy docs into Zeek repo directly

This is based on commit 99e6942efec5feff50523f6b2a1f5868f19ab638 from the
zeek-docs repo.

doc/devel/websocket-api/server.js

@@ -0,0 +1,23 @@
+// server.js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', (ws, req) => {
+  ws.on('error', console.error);
+  ws.on('close', () => { console.log('%s: gone', ws.zeek.app); });
+
+  ws.on('message', function message(data) {
+      console.log('%s: received: %s', ws.zeek.app, data);
+  });
+
+  let topics = ['zeek.bridge.test'];
+  let app = req.headers['x-application-name'] || '<unknown application>'
+  ws.zeek = {
+    app: app,
+    topics: topics,
+  };
+
+  console.log(`${app}: connected, sending topics array ${JSON.stringify(topics)}`);
+  ws.send(JSON.stringify(topics));
+});