Create new **image** excalidraw files.

[bric3]

Suggestion coming from [Alexander Schranz](https://plugins.jetbrains.com/author/51c5cbf1-a24f-40eb-b546-3a08899d3e1e),'s review.

Today you can directly edit myfile.excalidraw.png or myfile.excalidraw.svg files. However, the plugin does not yet support the creation of these formats.

TODO: See if adding file types like *.excalidraw.svg / *.excalidraw.png could fix the issue. Alos may require t handle empty image binary formats (with empty excalidraw payload)