There is the possibility of transforming private dashboards on shared dashboards?
Yes, create a new module. From that screen, highlight the module on the left pane and click the little "add page" button and select the Add User Pages option.
But to carry out such an operation would require that the user have a configuration license. How do he have access to modules with a license "Demand Management" or "Project Management'?
No Config license needed, but you do need Configure Modules and Distribute Modules access grants.