Add QoL scripts from Shosetsu Universe

[JFronny]

This includes Index Generation (which you said you wanted to look into) and, as such, depends on the relevant Shosetsu PRs being merged (this has now happened. Before it did, this used my own extension tester build, which meant this was not ready to be merged)
Specifically, this makes use of a Shosetsu extension tester build with these MRs:

• https://gitlab.com/shosetsuorg/kotlin-lib/-/merge_requests/69
• https://gitlab.com/shosetsuorg/extension-tester/-/merge_requests/4

and is a port of this MR: https://gitlab.com/shosetsuorg/extensions/-/merge_requests/526

Like that MR, this uses GitHub Pages (and requires it to be enabled and configured for GitHub Actions).
That said, it also automates index generation, so unless you remove the index from the repo (which is possible, since it is generated from scratch for Pages) existing users shouldn't be affected.

[jobobby04]

This looks great! Is there a reason you removed _doc.lua? Thats needed for the IDE to properly suggest and lint types and functions.

[JFronny]

In Shosetsu/Universe, it is downloaded by dev-setup. Since I added that here, having the file in git seemed redundant.
I can add it back, though.

[jobobby04]

I would prefer it be there by default, since I use different ones based on the branch I am on

[JFronny]

Since the MRs this depends on have been merged, this should now be ready for review

[jobobby04]

Can you make it so it uses https://jobobby04.github.io/ShosetsuExtensions/master/ instead? I plan to run multiple branches since I also will be adding this to my beta branch.

[JFronny]

As far as I can tell, GitHub Pages does not currently support pushing pages only to a subdirectory of the pages root (see this: actions/deploy-pages#349)
It should be possible to redesign the action to checkout both branches and generate a common pages artifact. When combined with a workflow for the other branches that simply calls this one, it would be possible to get that result.
This would lead to noticeably messier scripts though, so it's up to you whether I should try implementing this.

[jobobby04]

I found this action and it has a subdirectory option which might work https://github.com/marketplace/actions/github-pages-action#%EF%B8%8F-deploy-to-subdirectory-destination_dir

[JFronny]

That actions seems to work by committing the artifacts and, using a personal access token donated by some contributor, pushing to a branch in the repository, from which the artifacts are then published to Pages. Personally, I do not like that approach, but if you prefer it, it should be possible to use for this.

[jobobby04]

It sounds like it will fit my use-case better then the other action, so that sounds fine with me. I will create a token to use with this workflow.

[jobobby04]

A token has been created at DEPLOY_TOKEN.

[JFronny]

Done. I unfortunately cannot test this, but if the action isn't broken it should work.

[jobobby04]

Thanks for the work @JFronny! I was able to get it working exactly how I wanted, I have both my beta branch and master branch pushing to the gh-pages branch. I was able to get extension-tester and _doc.lua downloading from the correct places for each branch, it works perfectly.