Improve documentation website

I wanted to get up a basic docs website so that people could browse properties and such on the various NetSparkleUpdater classes. I used Natural Docs (quick Google result 😅) to generate some OK docs, and they are up now on the website here. I like that it makes a single page docs app sort of thing. However, I really don't like this setup for a few reasons:

• I have to manually update the docs by running the command line tool and push them to the branch that controls the website (gh-pages)
• The website is not very pretty.
• The docs aren't very...great....for example, enum values are not actually listed out. Maybe there is an option for this. I honestly didn't spend long on this haha
• Could use: https://github.com/marketplace/actions/doxygen-and-github-pages or https://github.com/marketplace/actions/doxygen-github-pages-deploy-action or similar

I would like to improve the docs on the website a lot, including integration of the details on this repo's README.md. I don't know what the options are here graphically. The repo also needs to be reconfigured (I think?) so that the docs website is a subfolder of the main repo instead of a separate branch so that CI/CD can generate and update the docs appropriately. There's some other files that get put on the website too so that the samples work, and we mustn't destroy any of those files or else the samples will stop working.

tl;dr: Need to get a better docs website up that can automatically update on CI/CD/repo push.

I'm open to suggestions!

Start by reviewing README.md, the existing documentation website, and the gh-pages branch to understand how generated docs and sample files are currently arranged. Define a CI/CD approach that incorporates README details, documents the C# classes and enum values, updates the site automatically, and preserves the files required by the samples.