docs: port to VitePress

Things that happen in this shameless squash:
- Removed 404 page
  - It doesn't work in VitePress and making it work in VitePress needs
    some invasive hack in the theme that I'm not willing to do
  - The default is more than enough, though
- Moved consoleVersionSelect include to another directory
  - This avoids being uploaded to Crowdin for translation
- Inline all SafeB9SInstaller includes
  - Not only do parameterized includes not work, but if/else statements
    don't work at all
- The sysupdate include parameter hasn't been used since MSET9, so it
  actually works just fine without any parameters. Hooray(?)
- Move mset9-chorus to an include, that logic doesn't work in VitePress
- Removed Get Started button from homepage, it breaks translations
- Tables in get-started are now shown by default; it seems VitePress really does
  not want us to use inline script. So we cannot enable it upon
  realizing that the browser is JS capable
- Include parameters are now in frontmatter to allow translation
- Hacked in a bunch of CSS values kanged from the old theme to make it
  look not stupid
- Drop headers down one level to make table of contents work

docs/h2testw-(windows).md

@@ -1,10 +1,6 @@
----
-title: "H2testw (Windows)"
----
+# H2testw (Windows)
 
-{% include toc title="Table of Contents" %}
-
-### Required Reading
+## Required Reading
 
 This is an add-on section for checking your SD card for errors using h2testw.
 
@@ -12,11 +8,11 @@ Depending on the size of your SD card and the speed of your computer, this proce
 
 This page is for Windows users only. If you are not on windows, check out the [F3 (Linux)](f3-(linux)) or [F3XSwift (Mac)](f3xswift-(mac)) pages.
 
-### What You Need
+## What You Need
 
 * The latest version of [h2testw](https://www.heise.de/ct/Redaktion/bo/downloads/h2testw_1.4.zip)
 
-### Instructions
+## Instructions
 
 1. Copy `h2testw.exe` from the h2testw `.zip` to your desktop
 1. Insert your SD card into your computer
@@ -28,13 +24,20 @@ This page is for Windows users only. If you are not on windows, check out the [F
 1. Click "Write + Verify"
 1. Wait until the process is completed
 
-___
+::: tip
 
 If the test shows the result `Test finished without errors`, your SD card is good and you can delete all `.h2w` files on your SD card.
-{: .notice--success}
+
+:::
+
+::: danger
 
 If the test shows any other results, your SD card may be corrupted or damaged and you may have to replace it!
-{: .notice--danger}
 
-### Return to [Get Started](get-started)
-{: .notice--primary}
+:::
+
+::: tip
+
+Return to [Get Started](get-started)
+
+:::