[Design] Onboarding to NEW desktop client 2.0

[teon]

Description

Since we have around 50k users of the client, and they are "normal" users - it is critical to have a new UI walkthrough first time they launch the 2.1 new client.

It needs to inform that:

1. The tray menu is the new client.
2. You can "Open Defguard" to see the old client.
3. There is a tray menu (right click).
4. And maybe a video? of connecting with MFA (yes we will bunde this video to be sure users know what to do).