[Feature] Link drag&drop

Many desktop programs support drag&dropping links from the client to other programs like the browser
This is extremely useful for tab management or when you're using multiple browsers/profiles/incognito mode
I'd love to see this added to the Keybase client

Here are examples of how it works in other chat clients: [Discord](https://i.imgur.com/hyscpg9.gif), [Telegram](https://i.imgur.com/YYzxnD8.gif)

Start by reviewing the Keybase client behavior and the linked Discord and Telegram examples. The issue names no files, tests, or implementation entry points, so the first task is to locate the desktop client area responsible for link interactions. Done means links can be dragged from the client into other programs, including browsers and browser profiles.

Written by the indexing model from the issue text.