Move tutorials to top level

[nwlandry]

This PR uses nbsphinx-link to move the tutorials back to the top level so that not only can nbsphinx render the notebooks for the website, but users can easily access the notebooks as well. This PR also fixes a few small extraneous things, namely:

• Now the encapsulation_dag page has the correct name
• We no longer use pkg_resources to determine the version and the contributing guide now reflects that.

[codecov[bot]]

Codecov Report

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

Project coverage is 92.35%. Comparing base (8ab20d8) to head (6dc809e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #550 +/- ## ========================================== - Coverage 92.35% 92.35% -0.01% ========================================== Files 60 60 Lines 4500 4499 -1 ========================================== - Hits 4156 4155 -1 Misses 344 344 ```

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[review-notebook-app[bot]]

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[nwlandry]

Thanks for the review, @thomasrobiglio! :D