update readme to remove insiders specific references + some cleanup

[IanMatthewHuff]

For #8548

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR).
• Title summarizes what is changing.
• Has a news entry file (remember to thank yourself!).
• Appropriate comments and documentation strings in the code.
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated.
• Test plan is updated as appropriate.
• package-lock.json has been regenerated by running npm install (if dependencies have changed).

[IanMatthewHuff]

I removed basically all !s out of a strong personal preference ;). However I'm totally willing to put them back in if I'm outvoted here.

[greazer]

Thanks for doing this Ian!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!... !!!!!!!! ! ! !

[codecov-commenter]

Codecov Report

Merging #8764 (8e688e7) into main (8b707fe) will increase coverage by 0%.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main   #8764   +/-   ##
=====================================
  Coverage     71%     72%           
=====================================
  Files        381     381           
  Lines      24535   24535           
  Branches    3772    3772           
=====================================
+ Hits       17640   17708   +68     
+ Misses      5379    5295   -84     
- Partials    1516    1532   +16     

Impacted Files	Coverage Δ
...tascience/jupyter/kernels/kernelCommandListener.ts	70% <0%> (-4%)	⬇️
...atascience/interactive-window/interactiveWindow.ts	67% <0%> (-2%)	⬇️
src/client/datascience/jupyter/kernelVariables.ts	59% <0%> (-2%)	⬇️
src/client/datascience/jupyter/kernels/helpers.ts	72% <0%> (-2%)	⬇️
...t/datascience/notebook/vscodeNotebookController.ts	80% <0%> (-1%)	⬇️
src/client/datascience/dataScienceSurveyBanner.ts	75% <0%> (ø)
src/client/datascience/commands/commandRegistry.ts	40% <0%> (+<1%)	⬆️
...datascience/jupyter/liveshare/hostJupyterServer.ts	75% <0%> (+<1%)	⬆️
src/client/datascience/baseJupyterSession.ts	76% <0%> (+<1%)	⬆️
src/client/datascience/jupyterDebugService.ts	17% <0%> (+1%)	⬆️
... and 25 more