Adding fsps demo; adding fsps set-up to smoke test

[OliviaLynn]

Problem & Solution Description (including issue #)

Moving in fsps notebook from Eric's branch in fsps

Also adding a step in the smoke test workflow to get fsps set up (required; see this failed run without the set-up step)

Final piece of #48

Code Quality

• [x] My code follows the code style of this project
• [x] Any breaking changes, described above, are accompanied by backwards compatibility and deprecation warnings

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (26bdfb7) 100.00% compared to head (d31b42f) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #118 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 1 1 Lines 1 1 ========================================= Hits 1 1 ```

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