Allow alternate authentication when generating from github private repo

[serbrech]

Is your feature request related to a problem? Please describe.

There is a feature to provide the github auth token to generate from a private repo URL. that's great, but it requires me to save my token somewhere.

interactive authentication flow

The github CLI provides an interactive authentication flow that is much nicer to use:

gh auth refresh      
! First copy your one-time code: 89EC-4BA4
Press Enter to open github.com in your browser... 
✓ Authentication complete.

I'd like autorest to have a similar option, either detecting the access denied, or via a auth flag such as --github-interactive-auth

SSH

Alternatively (both options would be great) allow to configure autorest to use my ssh key to find the files!

--ssh-key ~/.ssh/id_rsa