How to allow creation and deletion of a database or collections with user and password
No, system don't work that way. You must enable authentication and authorization of your mongodb. 

After that, you log in with userAdmin credentials and you (only) have authorization to do userAdmin work, not system admin work. But remember to create super-admin user (before enabling authenticaton) or you end up to situation that you don't have superuser (root) who can give other needed rights.