Coder Desktop Integration

[ThomasK33]

Implement an enhancement making this extension aware of Coder Desktop. With Coder Desktop running, there is already an established tunnel to a workspace; thus, the extension does not need to create another tunnel.

The extension should prioritize the existing tunnel rather than creating a new one and should be able to display tunnel statistics related to the VPN within the editor.

Related: coder/vscode-coder#447