update some metadata fields, sort deps

[bollwyvl]

This PR touches up setup.cfg in mostly cosmetic ways:

• applies whatever sorting my editor does (special casing for pyhon 3.10) for long lists
• removes the comment about installing the example project
  • downstreams actually use jupyter_server[test] so we can't use relative urls to things we don't distribute

Of particular note that will change how it appears on pypi.io:

• adds some trove classifiers
• adds some project URLs
• changes the home page to be the docs for this project
  • i don't think jupyter server is ever actually mentioned on the website

[codecov-commenter]

Codecov Report

Merging #675 (97dbadd) into main (f6f8c3f) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #675      +/-   ##
==========================================
+ Coverage   70.30%   70.32%   +0.01%     
==========================================
  Files          62       62              
  Lines        7554     7554              
  Branches     1248     1248              
==========================================
+ Hits         5311     5312       +1     
+ Misses       1860     1859       -1     
  Partials      383      383              

Impacted Files	Coverage Δ
jupyter_server/services/kernels/kernelmanager.py	79.66% <0.00%> (+0.33%)	⬆️

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[blink1073]

Thanks!