Java - Jetty - How to programmatically manage assets libs, css, img etc in Jetty-11 classpath outside web application root

Question

1. I have a web application that is deployed on external jetty server. NOT using embedded jetty.
2. Requirement, need a Java rest endpoint to manage assets like lib, js, css, image file etc in jetty folders that are outside my application web root.
3. Manage assets means, ability endpoints to upload assets, update assets, delete assets. Request help as to how i can achieve the same

A simple Rest endpoint can only access folders under web root.