Create a new role similar to the Administer Project role without permission to invite other users and grant Administrator permission, keeping the "configuring issue types and their fields, enabling project features, deleting a project, etc" permissions. 

 "We need to lock down Jira project permissions based on role. We are having a problem with Jira project admins adding other project admins outside of the role and need to restrict this. In other words, we need more granular permissions available in Jira projects. For example, we need to prevent project admins from modifying the user access to the project while still allowing them to edit all other aspects of the project. Does this make sense? This could be facilitated using custom admin roles."