JetBrains: Add connection notification
Created by: vdavid
Fixes https://github.com/sourcegraph/sourcegraph/issues/38802
This is what the notification looks like:
Important points:
- @philipp-spiess: I've added a way to test the connection on the Java side! It was pretty simple to do and is much nicer than depending on the browser.
- @jjinnii: I've added an extra "Open Soucegraph" button and some text, which I think is helpful to users. I can remove it if it's too much.
Test plan
App preview:
Check out the client app preview documentation to learn more.