Synchronize contents in multiple editors for same nb file

[DonJayamanne]

For #9340
Note

• This PR adds the infrastructure necessary to sync edits & the like across editors for the same file
• Code has been commented out to ensure some remaining bits work properly
• Waiting on some of the new changes from @rchiodo from his undo PR.

Remaining changes

• Ensuring we do not end up in a crazy loop that will cause one editor to propagate changes to the other, then that one back to this & so on
• Sync cell execution (currently creation of new cells isn't sync'ed across)
• Find a bullet proof solution for syncing focused states (this messes up everything - we don't need this in syncing editors, but if required for live share, then we need to ensure focus states work correctly - depending on whether liveshare even needs such a feature?)

[codecov-io]

Codecov Report

Merging #9886 into ds/custom_editor will decrease coverage by 0.01%.
The diff coverage is 25%.

@@                 Coverage Diff                 @@
##           ds/custom_editor   #9886      +/-   ##
===================================================
- Coverage             60.62%   60.6%   -0.02%     
===================================================
  Files                   555     555              
  Lines                 29737   29748      +11     
  Branches               4482    4484       +2     
===================================================
+ Hits                  18027   18029       +2     
- Misses                10709   10718       +9     
  Partials               1001    1001

Impacted Files	Coverage Δ
...ience/interactive-common/interactiveWindowTypes.ts	100% <100%> (ø)	⬆️
...ractive-common/interactiveWindowMessageListener.ts	17.02% <14.28%> (-0.48%)	⬇️
.../datascience/interactive-common/interactiveBase.ts	5.79% <25%> (-0.03%)	⬇️
src/datascience-ui/react-common/arePathsSame.ts	87.5% <0%> (ø)	⬆️
src/client/linters/pydocstyle.ts	88.63% <0%> (ø)	⬆️
src/client/datascience/debugLocationTracker.ts	78.12% <0%> (ø)	⬆️
src/client/common/process/proc.ts	15.21% <0%> (ø)	⬆️
src/client/common/utils/platform.ts	76.47% <0%> (ø)	⬆️

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[rchiodo]

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

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