jupyter compatible keybindings

[pfitzseb]

This switches our code-eval keybindings to something close to Jupyter and makes sure our kbds aren't used in jupyter notebooks.

[aviatesk]

lgtm, I would like to wait for approve from @davidanthoff before merging tho

[aviatesk]

Could you take a look at this, @davidanthoff ?
Well I think we can move forward with this anyway; afaiu the keybindings are just compatible with the Jupyter extension's.

[davidanthoff]

I would do this once the notebook stuff in base VS Code has shipped and we are sure that we know what their final choices will be.

[davidanthoff]

Or wait, is this not actually updating our keybindings, but just making sure that they are not used in the notebook UI? In that case, I'm in favor, of course.

[pfitzseb]

I was sneaky -- it does both. I actually thought the November release would finalize the Notebook API, but it turns out it didn't. It does seem very unlikely that the notebook keybindings will change though.