Support downloading artifact directly from Argo

[backjo]

Describe the solution you'd like
ArgoCD self-hosts artifacts for the CLI on it's web server. As a user, I'd like to be able to configure this action to download whatever version my self-hosted Argo is currently providing, for a few reasons:

• To keep my CD instance and the CLI in-sync automatically
• To avoid GH rate limiting when downloading artifacts

[bryantbiggs]

do you know the URL scheme where these artifacts can be pulled from?

[backjo]

Hey @bryantbiggs - it follows a format like https://argo-server/download/argocd-linux-amd64