Check role

[jpaulet]

As Vocdoni, we need to ensure that only users with the appropriate admin role can access certain sensitive pages, such as those for inviting new admins or creating new processes.

To achieve this, we require a function that verifies the role of the currently logged-in user and checks if they have the necessary permissions to access the requested page. If the user does not have the required permissions, a "No permissions" modal should be displayed to prevent unauthorized access.