workspace: add experimental pnpm support

packages/ui-default/backendlib/template.js

@@ -1,7 +1,5 @@
-const fs = require('fs');
 const path = require('path');
-const yaml = require('js-yaml');
-const serialize = require('serialize-javascript');
+const { serialize, fs, yaml } = require('hydrooj');
 const nunjucks = require('nunjucks');
 const jsesc = require('jsesc');
 const argv = require('cac')().parse();