device flow support

[kfox1111]

trafficstars

Purpose of the feature (why)

On multiuser systems such as hpc login nodes, it can be racy to open up tcp ports hosting webservers. It can be tricky to get a browser to reliably launch and display remotely to the user.

Your idea (how)

If configured with a device flow flag, kubelogin could use the device flow handshaking method with the oidc server, print out the url and device code to the user, and the user could use their own browser to do the authentication.