Support for local links

[lorefnon]

Hello, thanks for maintaining this project.

Since this extension can operate on local files, it would be nice to be able to also link to local files.

So if I have two files in a project source.excalidraw and target.excalidraw, I'd like to add some text in source.excalidraw and create a link that points to ./target.excalidraw. On clicking this link vscode would open the linked file in another tab.