Clean up notebooks build script

[bwohlberg]

Improve Python notebook build script, including removal of the need to exec a bash script. Remove makefile and bash script.

[codecov]

Codecov Report

Merging #108 (f7abee9) into main (76854da) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #108   +/-   ##
=======================================
  Coverage   90.48%   90.48%           
=======================================
  Files          42       42           
  Lines        3028     3028           
=======================================
  Hits         2740     2740           
  Misses        288      288           

Flag	Coverage Δ
unittests	90.48% <ø> (ø)

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[Michael-T-McCann]

I'm happy to see the makefile go, and I was able to use the new mechanism to build the examples on toro.