Include the Emscripten-built samples in our documentation page

[RiscadoA]

Problem

The Emscripten action we currently have uploads the sample results as artifacts to be downloaded.
It isn't practical for reviewers to test those samples, although it should be easy.
Additionally, it would be cool to have the samples hosted in our website, alongside their docs.

Solution

We should investigate improving the web build CI to include the built samples in their documentation pages.
These samples should appear in both the PR doc previews and on the final website deployment.
We avoid code duplication on those two scenarios, if possible.