Add a PySpark debug configuration for the experimental debugger

[DonJayamanne]

Fixes #1029

This pull request:

• Has a title summarizes what is changing
• Includes a news entry file
• Has unit tests & code coverage is not adversely affected (within reason)
• Works on all actively maintained versions of Python (e.g. Python 2.7 & the latest Python 3 release)
• Works on Windows 10, macOS, and Linux (e.g. considered file system case-sensitivity)

[codecov]

Codecov Report

Merging #1102 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1102      +/-   ##
==========================================
+ Coverage   71.67%   71.69%   +0.01%     
==========================================
  Files         260      260              
  Lines       11877    11877              
  Branches     2104     2104              
==========================================
+ Hits         8513     8515       +2     
+ Misses       3239     3238       -1     
+ Partials      125      124       -1

Impacted Files	Coverage Δ
...rc/client/debugger/PythonProcessCallbackHandler.ts	53.61% <0%> (+0.65%)	⬆️

---

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 ba97e02...599c2be. Read the comment docs.