napari should not install "benchmarks" as a toplevel package

[anntzer]

🐛 Bug

pip-installing napari not only creates a toplevel "napari" importable package, but also a spurious "benchmarks" package.

To Reproduce

Steps to reproduce the behavior:

In a clean venv, run pip install napari. Check that "benchmarks" has been installed as a toplevel package with e.g. python -c 'import benchmarks; print(benchmarks)'

Expected behavior

No such package installed.

Environment

This occurs when installing napari==0.2.10.

[sofroniewn]

Thanks for flagging @anntzer, this reminds me of #875 and would be good to fix alongside our other install improvements