Switch the default to Jupyter Server configuration file

[romainx]

Hello,

This is a follow-on to the PR #1575 in the frame of the issue #1217 aiming to switch to Jupyter Lab by default.
Since Jupyter Server is now the default backend, I think it's better to maintain it's configuration file jupyter_server_config.py instead of the Jupyter Notebook one jupyter_notebook_config.py.

• I've simply inverted in the Dockerfile the transformation between the two files.
• I've tried to update all the references in the doc, however I may have forgotten some.
• I've basically updated (search & replace) the files in the directory examples/openshift, however I'm not sure they are sill working 😕.

Best 🍰

[romainx]

The Sphinx check links fails because there is a link to a the file jupyter_server_config.py that does not yet exist on the master branch because it's part of this PR.

(    using/common: line  171) 
broken    https://github.com/jupyter/docker-stacks/blob/master/base-notebook/jupyter_server_config.py 
- 404 Client Error: Not Found for url: https://github.com/jupyter/docker-stacks/blob/master/base-notebook/jupyter_server_config.py

[mathbunnyru]

I've basically updated (search & replace) the files in the directory examples/openshift, however I'm not sure they are sill working

I feel the same way about the whole examples folder - I'm not sure they still work at all.

[mathbunnyru]

Thank you!
Once we decide to drop support for the old code, it will be a super-small change 👍

[romainx]

@mathbunnyru thanks a lot for the review and the merge! 👍