'okteto login showUrl' shows url, instead open browser

[kivi]

Fixes #615
also outputs the login url on cli, because on wsl2 a browser did not open and login timed out..

Proposed changes

• typing okteto login [url]
  Results into:

Authentication will continue in your default browser
You can also open a browser and navigate to the following address: https://cloud.okteto.com/github/authorization-code?redirect=someEncodedRedirectUrl
✓ Logged in as loginname
Run okteto namespace to switch your context and download your Kubernetes credentials.

[rberrelleza]

I think this is a good approach, I'd just show the URL all the time for now.

[rberrelleza]

Thanks for the contribution!