Add a saturation demo notebook

[jeremykubica]

Add more documentation on running the simulations and include a demo notebook about saturation.

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[github-actions]

Before [0181763]	After [d2600fd]	Ratio	Benchmark (Parameter)
2.34±0.6ms	2.48±0.9ms	1.06	benchmarks.TimeSuite.time_evaluate_simple_linear_wavelength_model
7.83±0.03ms	8.03±0.2ms	1.03	benchmarks.TimeSuite.time_apply_white_noise
7.72±0.04ms	7.84±0.1ms	1.02	benchmarks.TimeSuite.time_lightcurve_source
69.9±1ms	71.0±1ms	1.02	benchmarks.TimeSuite.time_make_and_evaluate_static_sed
54.1±1μs	55.1±0.7μs	1.02	benchmarks.TimeSuite.time_make_new_salt3_model
36.2±0.7μs	37.1±0.7μs	1.02	benchmarks.TimeSuite.time_make_simple_linear_wavelength_model
1.12±0.01s	1.14±0.01s	1.02	benchmarks.TimeSuite.time_make_x1_from_hostmass
121±2ms	122±2ms	1.01	benchmarks.TimeSuite.time_additive_multi_model_source
23.2±0.1ms	23.4±0.5ms	1.01	benchmarks.TimeSuite.time_chained_evaluate_sed
10.8±0.03ms	10.9±0.2ms	1.01	benchmarks.TimeSuite.time_load_passbands

Click here to view all benchmarks.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.42%. Comparing base (77d690a) to head (e4c711f).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #742      +/-   ##
==========================================
- Coverage   92.44%   92.42%   -0.02%     
==========================================
  Files          69       69              
  Lines        6430     6431       +1     
==========================================
  Hits         5944     5944              
- Misses        486      487       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.