In a composite project, supposing of having already user management in a module addon, how to create a single module application with no user management.
And in addition, is it possibile to create a single module addon with user management?
Take a look at this example project: https://github.com/jmix-projects/sample-composite-project
It has the structure you need: the users add-on provides user management, the sales application uses the add-on and doesn’t have its own user management.
There is no such templates yet, but you can easily arrange the required structure just by copy-pasting classes between subprojects.