Create Examples Gallery + Tests

[ecton]

The examples folder is already huge, as I have taken to the strategy of making a lot of micro-examples to demonstrate each feature. This means, however, that the directory is hard to navigate.

• Design a process to create recordings of the examples
• Create a CI job that records the examples and uploads the APNGs to dossier
• Create a README to live in the examples folder that presents the list of examples with some attempt at organization

[ecton]

I've moved the guide example capture process into cushy as an undocumented feature, and have hooked up the theme editor example to this system. The screenshot is now in the readme as a proof of concept.

Now the rest of the work is staging each of the examples and either creating screenshots or animations depending on what can show off the example the easiest.