Docs: Hide input/output prompts (cell counts) in the tutorial notebooks

[dcfidalgo]

Closes #249

[codecov]

Codecov Report

Merging #250 (87b82bf) into master (7cccb92) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #250   +/-   ##
=======================================
  Coverage   64.01%   64.01%           
=======================================
  Files         165      165           
  Lines        6388     6388           
=======================================
  Hits         4089     4089           
  Misses       2299     2299           

Flag	Coverage Δ
pytest	64.01% <ø> (ø)

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