need in-editor preview of tile, or at least identify tile to marker

Few ways could solve this
- Use icons for different tile types
- generate custom images with PIL that has text in
- Insert text with image to summarise tile settings
- insert a iframe? I don't think this allows preview however. plus we'd need a way to get round html filtering
- don't use images but instead use something that allows a preview?

For example a syntax similar to shortcodes such as

```
[[@@plone.app.contentlistingtile query="[{v:'type', o:'plone.app.querystring.operation.string.is', v:'Page'}]"]

[/@@plone.app.contentlistingtile]]
```

Users can change the settings of the tile themselves. If they change the preview html inbetween then it will get ignored. Alternatively some tiles might like to use the inbetween html as part of it's configuration?

Start by reviewing the existing TinyMCE tile insertion flow and the issue's proposed preview approaches. Determine the project behavior and scope needed to identify or preview a tile in the editor, then verify that users can distinguish tile settings before saving content.

Written by the indexing model from the issue text.