chore: Remove old integration pages (#17958)

#### Summary

Not sure why the Website build didn't fail in https://github.com/cloudquery/cloudquery/pull/17903, but it fails on `main`:

```
Error: No _configuration.md file found for source: firestore
--
15:37:38.719 | at <anonymous> (/vercel/path0/website/scripts/prebuild.tsx:166:17)
```

We shouldn't generate integration pages at all and redirect per https://github.com/cloudquery/cloudquery/pull/16681