Copy docs into Zeek repo directly

This is based on commit 2731def9159247e6da8a3191783c89683363689c from the
zeek-docs repo.

doc/scripting/js/api.js

@@ -0,0 +1,60 @@
+// api.js
+//
+// HTTP API allowing to invoke any Zeek events and functions using a simple JSON payload.
+//
+// Triggering and intel match (this will log to intel.log)
+//
+//     $ curl --data-raw '{"args": [{"indicator": "50.3.2.1", "indicator_type": "Intel::ADDR", "where":"Intel::IN_ANYWHERE"}, []]}' \
+//         http://localhost:8080/events/Intel::match
+//
+// Calling a Zeek function:
+//
+//     $ curl -XPOST --data '{"args": [1000]}' localhost:8080/functions/rand
+//     {
+//       "result": 730
+//     }
+//
+const http = require('node:http');
+
+// Light-weight safe-json-stringify replacement.
+BigInt.prototype.toJSON = function () { return parseInt(this.toString()); };
+
+const handleCall = (cb, req, res) => {
+  const name = req.url.split('/').at(-1);
+  const body = [];
+  req.on('data', (chunk) => {
+    body.push(chunk);
+  }).on('end', () => {
+    try {
+      const parsed = JSON.parse(Buffer.concat(body).toString() || '{}');
+      const args = parsed.args || [];
+      const result = cb(name, args);
+      res.writeHead(202);
+      return res.end(`${JSON.stringify({ result: result }, null, 2)}\n`);
+    } catch (err) {
+      console.error(`error: ${err}`);
+      res.writeHead(400);
+      return res.end(`${JSON.stringify({ error: err.toString() })}\n`);
+    }
+  });
+};
+
+const server = http.createServer((req, res) => {
+  if (req.method === 'POST') {
+    if (req.url.startsWith('/events/')) {
+      return handleCall(zeek.event, req, res);
+    } else if (req.url.startsWith('/functions/')) {
+      return handleCall(zeek.invoke, req, res);
+    }
+  }
+
+  res.writeHead(404);
+  return res.end();
+});
+
+const host = process.env.API_HOST || '127.0.0.1';
+const port = parseInt(process.env.API_PORT || 8080, 10);
+
+server.listen(port, host, () => {
+  console.log(`Listening on ${host}:${port}...`);
+});