Add example gallery to CI pipeline

[Pennycook]

Feature/behavior summary

We should explore the possibility of using GitHub actions to validate that changes do not break the example gallery.

Request attributes

• Would this be a refactor of existing code?
• Does this proposal require new package dependencies?
• Would this change break backwards compatibility?

Related issues

No response

Solution description

Create a new GitHub action that does the following:

• Run each of the examples and case-studies from the examples/ and case-studies/ directories.
• Extract the images produced.
• Attach the images to the workflow result as artifacts.

The action should pass as long as the examples execute correctly. We would still have to check the artifacts by eye.

Additional notes

No response

[Pennycook]

I'm setting this as required for 1.0.0 because I just found a few bugs when trying to re-generate the example gallery.