Add nodeenv instructions

linux/workstation/nodejs.markdown

+Node.js
+=======
+
+[nodejs](https://nodejs.org/) is a free, open-source, cross-platform JavaScript runtime environment that lets developers create servers, web apps, command line tools and scripts.
+
+Installation
+------------
+
+You can install nodejs as user on any linux workstation.
+Get the current stable [node version](https://nodejs.org/en) and install a prebuilt release using `nodeenv`:
+
+```sh
+mkdir -p "/scratch/${USER}"
+cd "/scratch/${USER}"
+nodeenv --node=22.13.1 --prebuilt .nodeenv
+source .nodeenv/bin/activate
+npm install -g --no-package-lock --no-save yarn
+```
+
+You should now have a `nodeenv` environment ready:
+
+```sh
+user@host:/scratch/user$ source .nodeenv/bin/activate
+user@host:/scratch/user$ node --version
+v22.13.1
+user@host:/scratch/user$ npm --version
+10.9.2
+user@host:/scratch/user$ yarn --version
+1.22.22
+```