[Feat]: Promote coder/coder in Get Started screen

[ammario]

Our new project is a natural extension of code-server and relevant to those attempting to set up code-server for their teams.

Let's add a loud callout to the Welcome Screen that says something to the effect of "Setting up code-server for a team? Check out coder/coder".

[jsjoeio]

To get to this, use Command Palette > Help: Get Started

Here's what it looks like: