Detect import errors for auto-installing

Some packages have optional dependencies that are only required for some functions. So importing the main package automatically installs it, but using it can still lead to an error. We can detect when this has happened to help users. It requires catching exceptions in `execute`, checking the caught exception as well as the chain of `__cause__` and `__context__` for `ModuleNotFoundError`, and looking at the `name` attribute. Then we tell the user to import the missing module explicitly to 'install' it.