use node: prefix for requires

mostly because code is being autogenerated by all the AI stuff using
this prefix. it's also used in the stack trace.

src/directoryserver.js

@@ -10,7 +10,7 @@ exports = module.exports = {
     checkCertificate,
 };
 
-const assert = require('assert'),
+const assert = require('node:assert'),
     AuditSource = require('./auditsource.js'),
     BoxError = require('./boxerror.js'),
     constants = require('./constants.js'),
@@ -19,14 +19,14 @@ const assert = require('assert'),
     ipaddr = require('./ipaddr.js'),
     groups = require('./groups.js'),
     ldap = require('ldapjs'),
-    path = require('path'),
+    path = require('node:path'),
     paths = require('./paths.js'),
     reverseProxy = require('./reverseproxy.js'),
     safe = require('safetydance'),
     settings = require('./settings.js'),
     shell = require('./shell.js')('directoryserver'),
     users = require('./users.js'),
-    util = require('util');
+    util = require('node:util');
 
 let gServer = null, gCertificate = null;