Add a glossary

[IchHabeHunger54]

This PR adds a glossary explaining several overall terms for modding in general and modding Minecraft specifically, as well as links for common "what is this" questions.

This glossary is explicitly not final and will never be. I expect it to be expanded over time.

Closes #110.

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Preview URL: https://pr-148.neoforged-docs-previews.pages.dev

[IchHabeHunger54]

for some reason the commit history is fucked up badly, i have no idea why

[neoforged-pages-deployments]

Deploying with Cloudflare Pages

Name	Result
Last commit:	7e723820547ead9d2ec118132dcd00db20822a4c
Status:	✅ Deploy successful!
Preview URL:	https://0a000737.neoforged-docs-previews.pages.dev
PR Preview URL:	https://pr-148.neoforged-docs-previews.pages.dev

[sciwhiz12]

What I would suggest, if you want to cleanup the commit history, is:

1. Force your local main branch to point to upstream/main (git fetch upstream, then git branch -f main upstream/main);
2. Checkout a temporary branch for your PR branch (git switch -c test);
3. Force your PR branch to match your main branch (git branch -f feature/glossary main);
4. Cherry-pick your one commit from the temporary branch to your fresh PR branch (git switch feature/glossary, then git cherry-pick test); and
5. Force-push your feature/glossary branch (and perhaps main too).

[HenryLoenwind]

Suggested change

	A coremod is the term for an ASM transformer file used within a mod. Traditionally, coremods were written as JavaScript files that were then loaded by a special coremod engine during [Forge][forge] or [NeoForge][neoforge] startup. More recently, Java coremods were developed as a more robust alternative. Coremods have a high entry barrier and are generally considered a last resort solution for most problems. Many problems can be solved easier using API methods, or using [mixins][mixin].
	Historically, the term "coremod" has also been incorrectly used for [library mods][librarymod].
	A coremod is the term for an ASM transformer file used within a mod. Originally written in Java, later as JavaScript files, they are then loaded by a special coremod engine during [Forge][forge] or [NeoForge][neoforge] startup. More recently, Java coremods were reintroduced as a more robust alternative. Coremods have a high entry barrier and are generally considered a last-resort solution for most problems. Many problems can be solved more easily using API methods or [mixins][mixin].
	As the older-style Java coremods had to maintain separation from mod code, they often were distributed as standalone mods. Over time, those evolved into code libraries, so the term "coremod" nowadays is often used incorrectly for any kind of [library mod][librarymod].