Add vega-lite as embedding object

Discussed in https://github.com/quarto-dev/quarto-cli/discussions/2868

^{Originally posted by aborruso October 15, 2022}
Hi,
it would be great to have in quarto for vega-lite, something like the Mermaid diagrams.

To write something like

``` {vega-lite}
{
  "data": {
    "values": [
      {"a": "C", "b": 2}, {"a": "C", "b": 7}, {"a": "C", "b": 4},
      {"a": "D", "b": 1}, {"a": "D", "b": 2}, {"a": "D", "b": 6},
      {"a": "E", "b": 8}, {"a": "E", "b": 4}, {"a": "E", "b": 7}
    ]
  },
  "mark": "point",
  "encoding": {
    "x": {"field": "a", "type": "nominal"}
  }
}
```

to get

Thank you