Remove some of ipython_genutils no-op.

[Carreau]

ipython_genutils is complicated to package on some linux distro because
of nose, and in general not useful as it mostly offered python 2/3
compat layer.

Goal always has been to remove any usage of ipython_genutils

[kevin-bates]

Thanks @Carreau - this looks good. I just had the one comment regarding the "duplicated" import.

[codecov-commenter]

Codecov Report

Merging #440 (b4d3403) into master (15d3782) will increase coverage by 0.46%.
The diff coverage is 69.56%.

❗ Current head b4d3403 differs from pull request most recent head d2ae127. Consider uploading reports for the commit d2ae127 to get more accurate results

@@            Coverage Diff             @@
##           master     #440      +/-   ##
==========================================
+ Coverage   77.75%   78.21%   +0.46%     
==========================================
  Files         106      106              
  Lines        9269     9622     +353     
  Branches      997     1100     +103     
==========================================
+ Hits         7207     7526     +319     
- Misses       1706     1717      +11     
- Partials      356      379      +23     

Impacted Files	Coverage Δ
jupyter_server/base/handlers.py	68.17% <0.00%> (+4.40%)	⬆️
jupyter_server/services/config/handlers.py	100.00% <ø> (ø)
jupyter_server/services/contents/fileio.py	75.26% <0.00%> (-0.13%)	⬇️
jupyter_server/services/contents/filemanager.py	66.88% <0.00%> (-0.08%)	⬇️
jupyter_server/services/contents/manager.py	88.28% <0.00%> (+0.49%)	⬆️
jupyter_server/services/kernels/kernelmanager.py	81.02% <0.00%> (-0.14%)	⬇️
jupyter_server/serverapp.py	72.94% <66.66%> (+5.81%)	⬆️
...upyter_server/services/contents/filecheckpoints.py	63.15% <100.00%> (ø)
jupyter_server/services/sessions/sessionmanager.py	86.88% <100.00%> (-0.11%)	⬇️
jupyter_server/tests/nbconvert/test_handlers.py	28.12% <100.00%> (ø)
... and 26 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 15d3782...d2ae127. Read the comment docs.

[Carreau]

rebased updated an pushed.

[blink1073]

Nice, thanks!

[welcome]

Congrats on your first merged pull request in this project! 🎉

Thank you for contributing, we are very proud of you! ❤️