[Docs] Move all inline `skaffold.yaml` snippets to `docs/content/en/samples`

Currently there exist skaffold config snippets strewn inline with rest of the docs. These can get stale very quickly. The correct place for these snippets is in [docs/content/en/samples](https://github.com/GoogleContainerTools/skaffold/tree/main/docs/content/en/samples) directory which has schema validations run as part of unit tests; and referenced in markdown using:
```
{{% readfile file="samples/path-to-file" %}}
```

> This is a tracking issue to scan the docs and relocate these snippets.