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/_include/id1-check.md

@@ -2,20 +2,32 @@ This occurs when you use multiple SD cards with the same 3DS and then merge the
 
 You will need to determine which one contains your data. First of all, back up all of the folders, in case something goes wrong:
 
+::: info
+
 ![Backup ID1](/images/screenshots/troubleshooting/backup-id1.png)
-{: .notice--info}
+
+:::
 
 Now, delete all but one of the folders from your SD card. Generally, you will want to delete the **smallest** one(s), as the one with all your data will probably have more space occupied. You can compare which folder is occupying more space by right-clicking it and clicking "Properties":
 
+::: info
+
 ![Properties prompt](/images/screenshots/troubleshooting/rightclick-properties.png)
-{: .notice--info}
+
+:::
+
+::: info
 
 ![Which to delete](/images/screenshots/troubleshooting/compare-id1.png)
-{: .notice--info}
+
+:::
 
 Your SD card should now look something like this:
 
+::: info
+
 ![Just enough ID1s](/images/screenshots/troubleshooting/correct-id1.png)
-{: .notice--info}
+
+:::
 
 Now, put your SD card into your 3DS and turn it on. If your data is still there, you deleted the right folder and have now determined your correct ID1. If everything has disappeared, go back into the backup folder that you made earlier and try the other folder.