Hello,
As I understood you need automatic setup and management of squid3 on ubuntu server, provided by [login to view URL] and upcloud.com.
I can build a CRUD tool that you can host on your webserver to act as a GUI for the background script.
It will have a create form where you can enter any custom meta data you need to have for the server (e.g. the hostname, SSH keys etc), after submitting this form it will connect to the API and create the server, then ssh into the server and setup & configure squid3.
You'll be able to view the status and manage servers with the same GUI.
If the GUI sounds an overkill for this tool, I can make it CLI based.
Let me know what works best for you and let's go over the details.
Best,
Nick.