add image support to docs

[lukehmcc]

Basically just the ability to paste from the clipboard, or upload from the machine with a button/hotkey. I don't think this issue is nearly as important as #35 #36 or #39 but it would be a nice feature to have if this is going to be a fully blown notes app.

[alexfreska]

👍 Agreed, going to create a block to do this that uploads the asset to the file system dac and embeds a reference.