Allow adding multiple URLs at once

[seansfkelley]

No description provided.

[noplanman]

@seansfkelley Any progress on this?
Should be quite straight-forward to implement, no?

[seansfkelley]

No progress; I only get time to work on this project sporadically. If you'd like to open a PR for it though I'd be happy to take a look.

[seansfkelley]

This might be as simple as splitting on newlines -- though for good UX, the feedback should mention how many things it's attempting to add (in the notification and in the dropdown, but hopefully also in the right-click menu?).