Forward gpg-agent to remote workspace

[Amanibhavam]

I didn't see an option for the VSCode Coder extension to forward gpg-agent to the workspace. I currently run coder ssh -G REMOTE in a background screen to forward my gpg-agent. It would be be great to have the gpg-agent forwarded by the extension so all the setup and errors occur in one place.

[deansheather]

We could probably accomplish this by launching a second SSH connection in the coder vscodessh subcommand for the sole purpose of forwarding. Seems like the main SSH connection is passed as a raw stream to vscode so we can't insert our own forwarders into it probably