Issues with 3.0.0-rc5 tutorial

[dsblank]

Description

Attempting to go through the jupyterlab_apod demo with jupyterlab 3.0.0-rc5

Reproduce

Followed directions. I think the point where my setup differs is that I was trying to install into ~/.local

Issues

1. jupyter_packaging was not mentioned until later, but is needed much earlier. Suggest adding pip install jupyter_packaging with jupyterlab
2. pip install -ve . does not work with --user; I had to use --prefix=~/.local
3. Even then, there is an error in where to put /share/ items.

$ pip install -ve . --prefix=/home/dblank/.local
...
Creating /home/dblank/.local/lib/python3.8/site-packages/jupyterlab-apod.egg-link (link to .)
Adding jupyterlab-apod 0.1.0 to easy-install.pth file

Installed /home/dblank/jupyterlab_apod
creating /usr/share/jupyter
error: could not create '/usr/share/jupyter': Permission denied

[dsblank]

Third issue is fixed with: jupyter/jupyter-packaging#52

[jasongrout]

Is the second issue also an issue with jupyter-packaging?

[dsblank]

@jasongrout I think there is something broken with python3.8 (or my local setup) and "pip install -e ." because I am getting the error on many packages.

In any event, I think my PR over on jupyter_packaging is now correct.

Thanks!