Add empty state for "Projects" panel in VS Code extension

[marko-hologram]

Issue

Currently, "Projects" panel inside the VS Code extension is fully empty if no projects are configured inside the workspace. "Last run" tab in comparison has empty state with a description describing that state and what to do.

With that "Projects" panel being empty like that, it seems like it's just broken. This is not a bug because I really don't have any projects defined in this workspace, but still it looks weird.

Potential solution

Maybe adding a some text like "No projects found in workspace. Learn how to set up projects --link to docs--" so that extension can point to docs and give some info why it's empty.

[milesj]

Good callout, is easy enough to add.