Add vscode command to add API key

[nang-dev]

Wondering if it is possible to add a command to add an API Key externally?

commands.registerCommand('extension.sayHello', () => {
window.showInformationMessage('Hello World!');
});

This would be non-intrusive, and allow for user scripts and native integrations into other code editors.

For full disclosure, I hope to recommend CLIne within PearAI as an end user - the extension gets downloaded from the marketplace as normal and the name Roo CLIne gets kept of course. Scripts would be run externally, and the user is encouraged to use CLIne within an editor of their choice if they so choose.

I can make a PR for this.