Add ability to view a slide deck in a browser

### What is the problem or limitation you are having?

Podium decks are, ultimately, folders of Markdown and stylesheets. It should be possible to view open Podium slide deck directly in a browser, without the direct involvement of Podium.

### Describe the solution you'd like

It should be possible to serve a Podium slide deck as a web page.

This probably won't be possible to do *completely* standalone, as there will be a need to reference external resources. However, it should be possible to publish a static website that contains Podium slide decks. For example, as a user, I should be able to publish a Github repository of all my talks, and have that content served as GitHub pages from a single repository.

### Describe alternatives you've considered

An alternative approach would be to modify the `slides.html` in the slide deck, and modify it to point at a "resources" URL at a known localhost port. This would require podium to exist and be serving resources at a known location, but it would allow a slide deck to be served.

### Additional context

_No response_

Start by examining the slide deck's slides.html and how it references resources. Compare the proposed static GitHub Pages use case with the localhost resources alternative. Done should mean a Podium deck can be served as a web page without direct involvement from Podium.

Written by the indexing model from the issue text.