Add an 'Examples' page to the docs with fully functioning example applications

There are a few cases of interesting usages that come up in issues, but which don't seem appropriate to put into our main docs (b/c we don't want to bloat our docs). If we had an Examples page in the docs, we could show off all of our cool ideas for how you can solve problems with webargs, but without disrupting the flow of the main documentation.

Specific cases which would be good candidates for example apps:

• Django App with CSRF-Removing Parser
• Axios Query-String Parser
• Setting a parser to use unknown=RAISE on query params

I did a quick scan of closed issues until I hit the 5.x/6.0 transition point, then called it a day. Maybe there are other interesting examples in older issues? Or maybe we have things in other parts of the docs like the upgrade guide which would be nice to separate out (or even just duplicate).

Beginne damit, die Kommentare zum verknüpften Issue zum Django CSRF-removing parser und zum Axios query-string parser zu prüfen, und untersuche anschließend die vorhandene webargs-Dokumentation und den Upgrade-Leitfaden auf weitere Kandidaten. Lege die Struktur der Examples page fest und wähle eine fokussierte Gruppe vollständig funktionsfähiger Anwendungen aus. Als erledigt gilt die Aufgabe, wenn die Seite und die ausführbaren Beispiele die vereinbarten Fälle abdecken, ohne die Hauptdokumentation aufzublähen.