Drag and drop compose similar to traditional mastodon

[dalekcoffee]

Clear and concise description of the problem

In elk.zone, if we wish to compose a message with media, we must click compose first, and THEN upload our media.

It would be really nice if we could begin a compose by dragging and dropping media into the page like on Mastodon

Suggested solution

Add the ability to begin composing a message if media is dragged/dropped

Vanilla mastodon example

Alternative

No response

Additional context

No response

[stackblitz[bot]]

Start a new pull request in StackBlitz Codeflow.

[ZMYaro]

I do not think Elk needs to change to support full screen drag-and-drop (especially since the resulting behavior may be unclear when the composer is not in view), but I think it would help if the drop zone outline in the composer became visible whenever dragging a valid file over the page so people know drag-and-drop is supported.