feat: add 'coming soon' empty state for projects page & gitignore public dir

- Add animated coming-soon card when no projects exist
- Add Grafana shortcode and gebrauchtwagen-datenbank project
- Add hugo/eliaskohout.de/public/ to .gitignore and remove from tracking

hugo/eliaskohout.de/hugo.toml

@@ -16,3 +16,6 @@ title = 'Elias Kohout'
 [[params.links]]
   name = "[r]ezepte"
   url  = "https://r.eliaskohout.de"
+
+[markup.goldmark.renderer]
+  unsafe = true