Fix documentation pipeline

[ernestum]

Next attempt at fixing the documentation pipeline.

Right now we had two issues:

1. we occasionally ran into timeouts when executing the tutorial notebooks.
2. we are missing dependencies when automatically generating API docs
3. The readthedocs.yaml file was not hidden.

I fixed 1 by increasing the timeout and splitting up the offending tutorial (GAIL) into more cells so we are less likely to run into the per-cell timeout.

Otherwise the config file was renamed and the dependencies were added.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (629ef9a) 95.64% compared to head (69ab819) 95.66%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #827      +/-   ##
==========================================
+ Coverage   95.64%   95.66%   +0.01%     
==========================================
  Files         102      102              
  Lines        9655     9655              
==========================================
+ Hits         9235     9236       +1     
+ Misses        420      419       -1     

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[ernestum]

@AdamGleave can you merge this one again? Looks like the first try of fixing the documentation pipeline fixed due to other issues which should have been fixed in this PR. Merging this one means another test run for LuaTex

[AdamGleave]

LGTM